S-4/A

Large accelerated filer

Accelerated filer

Non-accelerated filer

Smaller reporting company

Emerging growth company

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As filed with the U.S. Securities and Exchange Commission on

January 13, 2022.

No. 333-260692

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Amendment No. 2

FORM S-4

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

SUPERNOVA PARTNERS ACQUISITION COMPANY II, LTD.*

(Exact name of registrant as specified in its charter)


Cayman Islands*	6770	98-1574543
(State or other jurisdiction of incorporation or organization)	(Primary Standard Industrial Classification Code Number)	(I.R.S. Employer Identification No.)

4301 50

Street NW,

Suite 300 PMB 1044,

Washington, D.C. 20016

(202)

918-7050

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Robert D. Reid

Chief Executive Officer

Supernova Partners Acquisition Company II, Ltd.

4301 50th Street NW,

Suite 300 PMB 1044,

Washington, D.C. 20016

(202)

918-7050

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies of all communications, including communications sent to agent for service, should be sent to:


Patrick H. Shannon Latham & Watkins LLP 555 Eleventh Street, NW, Suite 1000 Washington, D.C. 20004 Tel: (202) 637-2200		Ryan J. Maierson Latham & Watkins LLP 811 Main Street, Suite 3700 Houston, TX 77002 Tel: (713) 546-5400		Adam Dinow Rupa Briggs David Silverman Cooley LLP 55 Hudson Yards New York, NY 10001 Tel: (212) 479-6000

Approximate date of commencement of proposed sale to the public

: As soon as practicable after this Registration Statement becomes effective and all other conditions to the transactions contemplated by the Agreement and Plan of Merger described in the included proxy statement/prospectus have been satisfied or waived.

If the securities being registered on this Form are being offered in connection with the formation of a holding company and there is compliance with General Instruction G, check the following box. ☐

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a

non-accelerated

filer, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule

12b-2

of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

If applicable, place an X in the box to designate the appropriate rule provision relied upon in conducting this transaction:

Exchange Act Rule

13e-4(i)

(Cross-Border Issuer Tender Offer) ☐

Exchange Act Rule 14d-l(d) (Cross-Border Third-Party Tender Offer)

☐

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CALCULATION OF REGISTRATION FEE



Title of Each Class of Securities to be Registered	Amount to be Registered (4)	Proposed Maximum Offering Price Per Unit	Proposed Maximum Aggregate Offering Price (1)	Amount of Registration Fee (9)
New Rigetti Common Stock (1)	148,012,213	$10.11 (5)	$1,496,396,488	$138,716 (8)
New Rigetti Common Stock (2)	13,075,000	$11.50 (6)	$150,362,500	$13,939 (8)
Warrants to purchase New Rigetti Common Stock (3)	13,075,000	$1.94 (7)	$25,365,500	$2,351 (8)
Total			$1,672,124,488	$155,006 (8)

(1)

The number of shares of common stock of New Rigetti (as defined below) being registered represents (i) 34,500,000 Class A ordinary shares underlying units issued in Supernova’s (as defined below) initial public offering which will be canceled and automatically converted, on

a one-for-one basis,

into shares of common stock of New Rigetti (the “New Rigetti Common Stock”); (ii) 8,625,000 Class B ordinary shares held by Supernova Partners II LLC, a Cayman Islands exempted company (the “Sponsor”) and each of Supernova’s directors and officers (which includes the Sponsor Earn Out Shares (as defined below)) which will be canceled and automatically converted, on

a one-for-one basis,

into shares of New Rigetti Common Stock; (iii) up to 78,153,546 shares of New Rigetti Common Stock that will be issued to the equityholders of Rigetti Holdings, Inc. (“Rigetti”) in connection with the Business Combination as defined and described in the proxy statement/prospectus forming part of this registration statement (the “proxy statement/prospectus”); and (iv) up to 26,733,667 shares of New Rigetti Common Stock reserved for issuance upon the exercise of options or warrants to purchase Rigetti common stock or settlement of restricted stock units for Rigetti common stock outstanding and that may be issued pursuant to the terms of the Merger Agreement described herein, which will convert into options or warrants to purchase New Rigetti Common Stock or restricted stock units for New Rigetti Common Stock in accordance with the terms of the Merger Agreement described herein.

(2)

Represents shares of New Rigetti Common Stock to be issued upon the exercise of (i) 8,625,000 warrants to purchase Class A ordinary shares underlying units issued in Supernova’s initial public offering (“public warrants”) and (ii) 4,450,000 warrants to purchase Class A ordinary shares underlying units issued in a private placement simultaneously with the closing of Supernova’s initial public offering (“private placement warrants,” and together with the public warrants, the “warrants”). The warrants will convert into warrants to acquire shares of New Rigetti Common Stock in the Business Combination and the Domestication (as defined below).

(3)	The number of warrants to acquire shares of New Rigetti Common Stock being registered represents (i) 8,625,000 public warrants and (ii) 4,450,000 private placement warrants.

(4)	Pursuant to Rule 416(a) of Securities Act of 1933, as amended (the “Securities Act”), there are also being registered an indeterminable number of additional securities as may be issued to prevent dilution resulting from stock splits, stock dividends or similar transactions.

(5)

Estimated solely for the purpose of calculating the registration fee, based on the average of the high and low prices of the Class A ordinary shares of Supernova on the New York Stock Exchange (“NYSE”) on October 26, 2021 ($10.11 per Class A ordinary share). This calculation is in accordance with Rule 457(f)(1) of the Securities Act.

(6)	Represents the exercise price of the warrants, as may be adjusted from time to time in accordance with the terms of the warrants.

(7)	Estimated solely for the purpose of calculating the registration fee, based on the average of the high and low prices of the Supernova public warrants on the NYSE on October 26, 2021 ($1.94 per warrant). This calculation is in accordance with Rule 457(f)(1) of the Securities Act.

(8)	Calculated by multiplying the proposed maximum aggregate offering price of securities to be registered by 0.0000927.

(9)	Previously paid.

Prior to (but no later than the day preceding) the consummation of the Business Combination, Supernova Partners Acquisition Company II, Ltd., a Cayman Islands exempted company (“Supernova”), intends to effect a deregistration under the Cayman Islands Companies Act (As Revised) and a domestication under Part XII of the Delaware General Corporation Law, pursuant to which Supernova’s jurisdiction of incorporation will be changed from the Cayman Islands to the State of Delaware (the “Domestication”). All securities being registered will be issued by the continuing entity following the Domestication, which will be renamed “Rigetti Computing, Inc.” upon the consummation of the Domestication. As used herein, “New Rigetti” refers to Supernova after giving effect to the consummation of the Domestication and the Business Combination.

The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act or until the registration statement shall become effective on such date as the SEC, acting pursuant to Section 8(a), may determine.

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The information in this preliminary proxy statement/prospectus is not complete and may be changed. The registrant may not sell the securities described in this preliminary proxy statement/prospectus until the registration statement filed with the Securities and Exchange Commission is declared effective. This preliminary proxy statement/prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

PRELIMINARY—SUBJECT TO COMPLETION, DATED JANUARY 13, 2022

PROXY STATEMENT FOR

EXTRAORDINARY GENERAL MEETING OF SUPERNOVA PARTNERS

ACQUISITION COMPANY II, LTD.

PROSPECTUS FOR 161,086,522

SHARES OF COMMON STOCK AND 13,075,000 WARRANTS OF SUPERNOVA PARTNERS ACQUISITION COMPANY II, LTD.

(AFTER ITS DOMESTICATION AS A CORPORATION INCORPORATED IN THE STATE OF DELAWARE, WHICH WILL BE RENAMED RIGETTI COMPUTING, INC. IN CONNECTION WITH THE DOMESTICATION DESCRIBED HEREIN)

The board of directors of Supernova Partners Acquisition Company II, Ltd., a Cayman Islands exempted company (“Supernova”), has unanimously approved the transactions (collectively, the “Business Combination”) contemplated by that certain Merger Agreement, dated October 6, 2021, as amended by Amendment No. 1 to Agreement and Plan of Merger dated as of December 23, 2021 and Amendment No. 2 to the Agreement and Plan of Merger dated as of January 10, 2022 (and as may be amended, supplemented or otherwise modified from time to time, the “Merger Agreement”), by and among Supernova, Supernova Merger Sub, Inc., a Delaware corporation (“First Merger Sub”), Romeo Supernova Merger Sub, LLC, a Delaware limited liability company (“Second Merger Sub”) and Rigetti Holdings, Inc. (“Rigetti”), a copy of which is attached to this proxy statement/prospectus as Annex A, including the domestication of Supernova as a Delaware corporation (the “Domestication”). As described in this proxy statement/prospectus forming part of this registration statement (the “proxy statement/prospectus”), Supernova’s shareholders are being asked to consider a vote upon each of the Domestication and the Business Combination, among other items. As used in this proxy statement/prospectus, “New Rigetti” refers to Supernova after giving effect to the consummation of the Domestication and the Business Combination.

In connection with the Domestication, immediately prior to (but no later than the day preceding) the date on which the closing of the Business Combination actually occurs (the “Closing Date”): (i) each issued and outstanding Class A ordinary share, par value $0.0001 per share (the “Class A ordinary shares”), and each issued and outstanding Class B ordinary share, par value $0.0001 per share (the “Class B ordinary shares”), of Supernova will be converted into one share of common stock, par value $0.0001 per share, of New Rigetti (the “New Rigetti Common Stock”); (ii) each issued and outstanding whole warrant to purchase Class A ordinary shares of Supernova will automatically represent the right to purchase one share of New Rigetti Common Stock at an exercise price of $11.50 per share on the terms and conditions set forth in the Warrant Agreement between American Stock Transfer & Trust Company, LLC and Supernova Partners Acquisition Company II, Ltd., dated February 23, 2021 (the “Supernova warrant agreement”); (iii) each issued and outstanding Supernova preference share will continue to exist as a share of preferred stock of New Rigetti; (iv) the governing documents of Supernova will be amended and restated and become the certificate of incorporation and the bylaws of New Rigetti as described in this proxy statement/prospectus; and (v) Supernova’s name will change to “Rigetti Computing, Inc.” In connection with clauses (i) and (ii) of this paragraph, each issued and outstanding unit of Supernova that has not been previously separated into the underlying Class A ordinary shares of Supernova and the underlying warrants of Supernova prior to the Domestication will be cancelled and will entitle the holder thereof to one share of New Rigetti Common Stock and

one-fourth

of one warrant representing the right to purchase one share of New Rigetti Common Stock at an exercise price of $11.50 per share on the terms and subject to the conditions set forth in the Supernova warrant agreement.

On the Closing Date, First Merger Sub will merge with and into Rigetti, with Rigetti surviving such merger as a wholly owned subsidiary of New Rigetti, followed by the Second Merger, whereby, immediately following and as part of the same overall transaction as the First Merger, Rigetti will merge with and into Second Merger Sub, with Second Merger Sub surviving such merger as a wholly owned subsidiary of New Rigetti (the “Merger” and the time that the Merger becomes effective being referred to as the “Effective Time”).

In accordance with the terms and subject to the conditions of the Merger Agreement, at the Effective Time, each share of Rigetti outstanding as of immediately prior to the Effective Time will be exchanged for shares of New Rigetti Common Stock based on an implied Rigetti equity value of $1,041,000,000, each Rigetti option or warrant will convert into options or warrants to purchase New Rigetti Common Stock and each Rigetti Restricted Stock Unit Award will convert into restricted stock units for New Rigetti Common Stock. The market value of the shares to be issued could vary significantly from the market value as of the date of this proxy statement/prospectus.

Concurrently with the execution of the Merger Agreement, Supernova entered into Subscription Agreements (the “Initial Subscription Agreements”) with certain investors (together, the “Initial PIPE Investors”), pursuant to which the Initial PIPE Investors have agreed to subscribe for and purchase, and Supernova has agreed to issue and sell to the Initial PIPE Investors, an aggregate of 10,251,000 shares of New Rigetti Common Stock at a price of $10.00 per share, for aggregate gross proceeds of $102,510,000 (the “Initial PIPE Financing”). On December 23, 2021, Supernova entered into

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Subscription Agreements (the “Subsequent Subscription Agreements”, and together with the Initial Subscription Agreements, the “Subscription Agreements”) with two “accredited investors” (as such term is defined in Rule 501 of Regulation D) (the “Subsequent PIPE Investors”, and together with the Initial PIPE Investors, the “PIPE Investors”) pursuant to which the Subsequent PIPE Investors have agreed to subscribe for and purchase, and Supernova has agreed to issue and sell to the Subsequent PIPE Investors, an aggregate of 4,390,244 shares of New Rigetti Common Stock at a price of $10.25 per share, for aggregate gross proceeds of $45,000,000 (the “Subsequent PIPE Financing, and together with the Initial PIPE Financing, the “PIPE Financing”). The shares of New Rigetti Common Stock to be issued pursuant to the Subscription Agreements have not been registered under the Securities Act of 1933, as amended (the “Securities Act”) in reliance upon the exemption provided in Section 4(a)(2) of the Securities Act and/or Rule 506(c) promulgated thereunder. Supernova will grant the PIPE Investors certain registration rights in connection with the PIPE Financing. The PIPE Financing is contingent upon, among other things, the substantially concurrent closing of the Business Combination.

It is anticipated that, upon completion of the Business Combination, (i) existing shareholders of Rigetti will own approximately 59% of New Rigetti on an undiluted basis; (ii) Supernova’s public shareholders (other than the PIPE Investors) will retain an ownership interest of approximately 26% in New Rigetti on an undiluted basis; (iii) the PIPE Investors (which includes the Sponsor) will own approximately 11% of New Rigetti on an undiluted basis; and (iv) Supernova Partners II LLC, a Cayman Islands exempted company (the “Sponsor”) (and its affiliates) will own approximately 4% of New Rigetti (which amount excludes shares purchased by the Sponsor in the PIPE and excludes Sponsor Earn Out Shares), in each case, assuming that none of Supernova’s outstanding public shares are redeemed in connection with the Business Combination, or approximately 76%, 5%, 14% and 5%, respectively, assuming that approximately 84% of Supernova’s outstanding public shares are redeemed in connection with the Business Combination. These percentages (i) assume that 78,153,546 shares of New Rigetti Common Stock are issued to the holders of shares of common stock and preferred stock of Rigetti at Closing, which would be the number of shares of New Rigetti Common Stock issued to these holders if Closing were to occur on September 30, 2021; (ii) are based on 14,641,244 shares of New Rigetti Common Stock to be issued in the PIPE Financing; (iii) do not take into account any exercise of public warrants or private placement warrants to purchase New Rigetti Common Stock that will be outstanding immediately following Closing; and (iv) do not take into account any shares of New Rigetti Common Stock underlying vested and unvested options, warrants, or restricted stock units that will be held by equityholders of Rigetti immediately following Closing. If the actual facts are different than these assumptions, the ownership percentages in New Rigetti will be different. See “

Summary of the proxy statement/prospectus—Ownership of New Rigetti

” for more information.

This prospectus covers up to 161,086,522 shares of New Rigetti Common Stock (including shares issuable upon exercise of the options and warrants and restricted stock units described above) and up to 13,075,000 warrants to acquire shares of New Rigetti Common Stock to be issued in connection with the Domestication. The number of shares of New Rigetti Common Stock that this prospectus covers represents the maximum number of shares that may be issued to holders of shares, options, warrants or Rigetti Restricted Stock Unit Awards in connection with the Business Combination (as more fully described in this proxy statement/prospectus), together with the shares issued or issuable to the existing shareholders and warrant holders of Supernova in connection with the Business Combination.

Supernova’s units, public shares and public warrants are currently listed on New York Stock Exchange (the “NYSE”) under the symbols “SNII.U,” “SNII” and “SNII WS,” respectively. Supernova will apply for listing, to be effective at the time of the Business Combination, of New Rigetti Common Stock and warrants on Nasdaq under the proposed symbols “RGTI” and “RGTI WS,” respectively. It is a condition of the consummation of the Business Combination that Supernova receive confirmation from Nasdaq that New Rigetti has been conditionally approved for listing on Nasdaq, but there can be no assurance such listing condition will be met or that Supernova will obtain such confirmation from Nasdaq. If such listing condition is not met or if such confirmation is not obtained, the Business Combination will not be consummated unless the stock exchange condition set forth in the Merger Agreement is waived by the applicable parties.

The accompanying proxy statement/prospectus provides shareholders of Supernova with detailed information about the Business Combination and other matters to be considered at the extraordinary general meeting of Supernova. We encourage you to read the entire accompanying proxy statement/prospectus, including the Annexes and other documents referred to therein, carefully and in their entirety. You should also carefully consider the risk factors described in “

Risk Factors

” beginning on page 59 of the accompanying proxy statement/prospectus.

NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES REGULATORY AGENCY HAS APPROVED OR DISAPPROVED THE TRANSACTIONS DESCRIBED IN THE ACCOMPANYING PROXY STATEMENT/PROSPECTUS, PASSED UPON THE MERITS OR FAIRNESS OF THE BUSINESS COMBINATION OR RELATED TRANSACTIONS OR PASSED UPON THE ADEQUACY OR ACCURACY OF THE DISCLOSURE IN THE ACCOMPANYING PROXY STATEMENT/PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY CONSTITUTES A CRIMINAL OFFENSE.

The accompanying proxy statement/prospectus is dated , 2022, and is first being mailed to Supernova’s shareholders on or about , 2022.

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SUPERNOVA PARTNERS ACQUISITION COMPANY II, LTD.

4301 50th Street NW,

Suite 300 PMB 1044,

Washington, D.C. 20016

Dear Supernova Partners Acquisition Company II, Ltd. Shareholders:

You are cordially invited to attend the extraordinary general meeting (the “extraordinary general meeting”) of Supernova Partners Acquisition Company II, Ltd., a Cayman Islands exempted company (“Supernova”), at , Eastern Time, on , 2022, at the offices of located at , and virtually via live webcast at , on such other date and at such other place to which the meeting may be adjourned. As all shareholders are no doubt aware, due to the current novel coronavirus

(“COVID-19”)

global pandemic, there are restrictions in place in many jurisdictions relating to the ability to conduct

in-person

meetings. As part of our precautions regarding

COVID-19,

As further described in the accompanying proxy statement/prospectus, in connection with the Domestication (as defined below), immediately prior to (but no later than the day preceding) the date on which the closing of the Domestication (as defined below), the Merger (as defined below) and other transactions contemplated by the Merger Agreement (as defined below), collectively, including the PIPE Financing (as defined below); (the “Business Combination”) actually occurs ( the “Closing Date”), among other things, (i) Supernova will change its name to “Rigetti Computing, Inc.,” (ii) all of the outstanding shares of Supernova will be converted into common stock of a new Delaware corporation and all of the outstanding Supernova warrants will be converted into warrants to purchase common stock of a new Delaware corporation, and (iii) the governing documents of Supernova will be amended and restated. As used in the accompanying proxy statement/prospectus, “New Rigetti” refers to Supernova after giving effect to the Domestication and the Business Combination.

At the extraordinary general meeting, Supernova shareholders will be asked to consider and vote upon a proposal, which is referred to herein as the “Business Combination Proposal,” to approve and adopt the Merger Agreement, dated as of October 6, 2021 (as may be amended, supplemented or otherwise modified from time to time, the “Merger Agreement”), by and among Supernova, Supernova Merger Sub, Inc., a Delaware corporation (“First Merger Sub”), Supernova Romeo Merger Sub, LLC, a Delaware limited liability company (“Second Merger Sub”) and Rigetti Holdings, Inc., a Delaware corporation (“Rigetti”), a copy of which is attached to the accompanying proxy statement/prospectus as Annex A, and the transactions contemplated thereby.

As further described in the accompanying proxy statement/prospectus, subject to the terms and conditions of the Merger Agreement, the following transactions will occur:

(1) Immediately prior to (but no later than the day preceding) the Closing Date, Supernova will change its jurisdiction of incorporation by deregistering as a Cayman Islands exempted company and continuing and domesticating as a corporation incorporated under the laws of the State of Delaware (the “Domestication”), upon which Supernova will change its name to “Rigetti Computing, Inc.” (“New Rigetti”) (for further details, see “

The Domestication Proposal

”).

(2) First Merger Sub will merge with and into Rigetti, with Rigetti surviving such merger as a wholly owned subsidiary of New Rigetti, followed by the Second Merger, whereby, immediately following and as part of the same overall transaction as the First Merger, Rigetti will merge with and into Second Merger Sub, with Second Merger Sub surviving such merger as a wholly owned subsidiary of New Rigetti (the “Merger” and the time that the Merger becomes effective being referred to as the “Effective Time”). In accordance with the terms and subject to the conditions of the Merger Agreement, at the Effective Time, each share of Rigetti outstanding

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as of immediately prior to the Effective Time will be exchanged for shares of New Rigetti Common Stock based on an implied Rigetti equity value of $1,041,000,000, each Rigetti option or warrant will convert into options or warrants to purchase New Rigetti Common Stock and each Rigetti Restricted Stock Unit Award will convert into restricted stock units for New Rigetti Common Stock.

In connection with the foregoing and concurrently with the execution of the Merger Agreement, Supernova entered into Subscription Agreements (the “Initial Subscription Agreements”) with certain investors (together, the “Initial PIPE Investors”), pursuant to which the Initial PIPE Investors have agreed to subscribe for and purchase, and Supernova has agreed to issue and sell to the Initial PIPE Investors, an aggregate of 10,251,000 shares of New Rigetti Common Stock at a price of $10.00 per share, for aggregate gross proceeds of $102,510,000 (the “Initial PIPE Financing”). On December 23, 2021, Supernova entered into Subscription Agreements (the “Subsequent Subscription Agreements”, and together with the Initial Subscription Agreements, the “Subscription Agreements”) with two “accredited investors” (as such term is defined in Rule 501 of Regulation D) (the “Subsequent PIPE Investors”, and together with the Initial PIPE Investors, the “PIPE Investors”) pursuant to which the Subsequent PIPE Investors have agreed to subscribe for and purchase, and Supernova has agreed to issue and sell to the Subsequent PIPE Investors, an aggregate of 4,390,244 shares of New Rigetti Common Stock at a price of $10.25 per share, for aggregate gross proceeds of $45,000,000 (the “Subsequent PIPE Financing, and together with the Initial PIPE Financing, the “PIPE Financing”). The shares of New Rigetti Common Stock to be issued pursuant to the Subscription Agreements have not been registered under the Securities Act of 1933, as amended (the “Securities Act”) in reliance upon the exemption provided in Section 4(a)(2) of the Securities Act and/or Rule 506(c) promulgated thereunder. Supernova will grant the PIPE Investors certain registration rights in connection with the PIPE Financing. The PIPE Financing is contingent upon, among other things, the substantially concurrent closing of the Business Combination (the “Closing”).

You will also be asked to consider and vote upon (a) a proposal to approve by special resolution the adoption and approval of the proposed new certificate of incorporation and proposed new bylaws of New Rigetti (the “Proposed Charter and Bylaws Proposal”), (b) four (4) separate proposals, each as an ordinary resolution and on a

non-binding

advisory basis, to approve material differences between Supernova’s existing amended and restated memorandum and articles of association (the “Existing Governing Documents”) and the proposed new certificate of incorporation of New Rigetti and the proposed new bylaws of New Rigetti upon the Domestication, copies of which are attached to the accompanying proxy statement/prospectus as Annexes C and D, respectively, which are referred to herein collectively as the “Advisory Governing Documents Proposals,” (c) a proposal to approve, for purpose of complying with Rule 312.03 of the NYSE Listed Company Manual, the issuance of the 14,641,244 shares of Rigetti Common Stock immediately prior to the Closing of the Business Combination in connection with the PIPE Financing and the New Rigetti Common Stock to be issued in connection with the Business Combination, which is referred to herein as the “Stock Issuance Proposal” (d) a proposal to elect directors who, upon consummation of the Business Combination, will be the directors of New Rigetti, which is referred to herein as the “Director Election Proposal”, (e) a proposal to approve and adopt the New Rigetti 2022 Equity Incentive Plan, a copy of which is attached to the accompanying proxy statement/prospectus as Annex H, which is referred to herein as the “Equity Incentive Plan Proposal,” (f) a proposal to approve and adopt the New Rigetti 2022 Employee Stock Purchase Plan, a copy of which is attached to the accompanying proxy statement/prospectus as Annex I, which is referred to herein as the “Employee Stock Purchase Plan Proposal,” and (g) a proposal to adjourn the extraordinary general meeting to a later date or dates which is referred to herein as the “Adjournment Proposal.”

The Business Combination will be consummated only if the Business Combination Proposal, the Domestication Proposal, the Proposed Charter and Bylaws Proposal, the Equity Incentive Plan Proposal, the Employee Stock Purchase Plan Proposal, the Stock Issuance Proposal and the Director Election Proposal (collectively, the “Condition Precedent Proposals”) are approved at the extraordinary general meeting. The Advisory Governing Documents Proposals are

non-binding

advisory proposals that are not conditions precedent to the consummation of the Business Combination and a vote against will have no impact on the provisions of the new certificate of incorporation or new bylaws of New Rigetti. The Adjournment Proposal is not conditioned upon the approval of

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any other proposal. Each of these proposals is more fully described in the accompanying proxy statement/prospectus, which each shareholder is encouraged to read carefully and in its entirety.

The Adjournment Proposal provides for a vote to adjourn the extraordinary general meeting to a later date or dates (i) to solicit additional proxies for the purpose of obtaining approval by the shareholders of Supernova for each of the proposals necessary to consummate the transactions contemplated by the Merger Agreement, (ii) for the absence of a quorum or (iii) if the holders of the Class A ordinary shares have elected to redeem a number of Class A ordinary shares as of such time that would reasonably be expected to result in the conditions required for the Closing of the Merger Agreement not to be satisfied; provided that, without the consent of Rigetti, in no event shall the extraordinary general meeting of shareholders be adjourned to a date that is more than fifteen (15) business days later than the most recently adjourned meeting or to a date that is five (5) business days prior to the termination date of the Merger Agreement.

In connection with the Business Combination, certain related agreements have been, or will be entered into at or prior to the closing of the Business Combination, including the Subscription Agreements, Rigetti Holder Support Agreement, the Sponsor Support Agreement and the Registration Rights Agreement (each as defined in the accompanying proxy statement/prospectus). See “

Business Combination Proposal—Related Agreements

” in the accompanying proxy statement/prospectus for more information.

Pursuant to the Existing Governing Documents, a holder of Supernova’s public shares (a “public shareholder”) may request that Supernova redeem all or a portion of such public shares for cash if the Business Combination is consummated. Holders of units must elect to separate the units into the underlying public shares and warrants prior to exercising redemption rights with respect to the public shares. If holders hold their units in an account at a brokerage firm or bank, holders must notify their broker or bank that they elect to separate the units into the underlying public shares and warrants, or if a holder holds units registered in its own name, the holder must contact American Stock Transfer & Trust Company (“AST”), Supernova’s transfer agent, directly and instruct it to do so. The redemption rights include the requirement that a holder must identify itself in writing as a beneficial holder and provide its legal name, phone number and address to AST in order to validly redeem its shares.

Public shareholders may elect to redeem their public shares even if they vote “for” the Business Combination Proposal.

If the Business Combination is not consummated, the public shares will be returned to the respective holder, broker or bank. If the Business Combination is consummated, and if a public shareholder properly exercises its right to redeem all or a portion of the public shares that it holds and timely delivers its share certificates (if any) and other redemption forms (as applicable) to AST, New Rigetti will redeem such public shares for a

per-share

price, payable in cash, equal to the pro rata portion of the trust account established at the consummation of Supernova’s initial public offering, calculated as of two business days prior to the consummation of the Business Combination. For illustrative purposes, as of September 30, 2021, this would have amounted to approximately $10.00 per issued and outstanding public share. If a public shareholder exercises its redemption rights in full, then it will be electing to exchange its public shares for cash and will no longer own public shares. See “

Extraordinary General Meeting of Supernova—Redemption Rights

” in the accompanying proxy statement/prospectus for a detailed description of the procedures to be followed if you wish to redeem your public shares for cash.

Notwithstanding the foregoing, a public shareholder, together with any affiliate of such public shareholder or any other person with whom such public shareholder is acting in concert or as a “group” (as defined in Section 13(d)(3) of the Securities Exchange Act of 1934, as amended (“Exchange Act”)), will be restricted from redeeming its public shares with respect to more than an aggregate of 15% of the public shares. Accordingly, if a public shareholder, alone or acting in concert or as a group, seeks to redeem more than 15% of the public shares, then any such shares in excess of that 15% limit would not be redeemed for cash.

Supernova Partners II LLC, a Cayman Islands exempted company (the “Sponsor”) and each of our directors and officers (collectively, the “Initial Shareholders”) have, pursuant to the sponsor support agreement with the Sponsor, Rigetti and Supernova’s directors and officers (the “Sponsor Support Agreement”), agreed to, among

iii

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other things, vote all of their ordinary shares in favor of the proposals being presented at the extraordinary general meeting and waive its anti-dilution rights with respect to their Class B ordinary shares in connection with the consummation of the Business Combination. Such shares will be excluded from the pro rata calculation used to determine the

per-share

redemption price. As of the date of the accompanying proxy statement/prospectus, the Initial Shareholders own approximately 20% of the issued and outstanding ordinary shares. See “

Business Combination Proposal—Related Agreements—Sponsor Support Agreement

” in the accompanying proxy statement/prospectus for more information related to the Sponsor Support Agreement.

The Merger Agreement is subject to the satisfaction or waiver of certain other closing conditions as described in the accompanying proxy statement/prospectus. There can be no assurance that the parties to the Merger Agreement would waive any such closing condition. In addition, in no event will Supernova redeem public shares in an amount that would cause New Rigetti’s net tangible assets (as determined in accordance with Rule

3a51-1(g)(1)

of the Exchange Act) to be less than $5,000,001 after giving effect to the transactions contemplated by the Merger Agreement and the PIPE Financing.

Supernova is providing the accompanying proxy statement/prospectus and accompanying proxy card to Supernova’s shareholders in connection with the solicitation of proxies to be voted at the extraordinary general meeting and at any adjournments of the extraordinary general meeting. Information about the extraordinary general meeting, the Business Combination and other related business to be considered by Supernova’s shareholders at the extraordinary general meeting is included in the accompanying proxy statement/prospectus.

Whether or not you plan to attend the extraordinary general meeting, all of Supernova’s shareholders should read the accompanying proxy statement/prospectus, including the Annexes and other documents referred to therein, carefully and in their entirety. You should also carefully consider the risk factors described in

“

Risk Factors

”

beginning on page 59 of the accompanying proxy statement/prospectus

After careful consideration, the board of directors of Supernova has unanimously approved the Merger Agreement and the transactions contemplated thereby, including the Merger, and unanimously recommends that shareholders vote “FOR” the adoption of the Merger Agreement and approval of the transactions contemplated thereby, including the Merger, and “FOR” all other proposals presented to Supernova’s shareholders in the accompanying proxy statement/prospectus. When you consider the recommendation of these proposals by the board of directors of Supernova, you should keep in mind that the Sponsor and Supernova’s directors and officers have interests in the Business Combination that may conflict with your interests as a shareholder. See the section entitled “

Business Combination Proposal—Interests of Supernova’s Sponsor, Directors and Executive Officers in the Business Combination

” in the accompanying proxy statement/prospectus for a further discussion of these considerations.

The approval of each of the Domestication Proposal and the Proposed Charter and Bylaws Proposal requires a special resolution under Cayman Islands law, being the affirmative vote of the holders of at least

two-thirds

(2/3) of the ordinary shares who, being present in person or by proxy and entitled to vote at the extraordinary general meeting, vote at the extraordinary general meeting. The approval of each of the Business Combination Proposal, each of the Advisory Governing Documents Proposals, the Stock Issuance Proposal, the Director Election Proposal, the Equity Incentive Plan Proposal, the Employee Stock Purchase Plan Proposal and the Adjournment Proposal requires an ordinary resolution under Cayman Islands law, being the affirmative vote of a majority of the ordinary shares represented in person or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting, vote at the extraordinary general meeting. Because the Domestication Proposal involves a vote to continue Supernova outside the jurisdiction of the Cayman Islands, holders of Class B ordinary shares will have ten votes per Class B ordinary share and holders of Class A ordinary shares will have one vote per Class A ordinary share for purposes of the Domestication Proposal. Holders of Class B ordinary shares and Class A ordinary shares shall have one vote per share on all other proposals.

Your vote is very important

. Whether or not you plan to attend the extraordinary general meeting, please vote as soon as possible by following the instructions in the accompanying proxy statement/prospectus to make sure that your shares are represented at the extraordinary general meeting. If you hold your shares

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in “street name” through a bank, broker or other nominee, you will need to follow the instructions provided to you by your bank, broker or other nominee to ensure that your shares are represented and voted at the extraordinary general meeting. The Business Combination will be consummated only if the Condition Precedent Proposals are approved at the extraordinary general meeting. Each of the Condition Precedent Proposals is cross-conditioned on the approval of each other Condition Precedent Proposal. The Advisory Governing Documents Proposals are

non-binding

If you sign, date and return your proxy card without indicating how you wish to vote, your proxy will be voted FOR each of the proposals presented at the extraordinary general meeting. If you fail to return your proxy card or fail to instruct your bank, broker or other nominee how to vote, and do not attend the extraordinary general meeting in person, the effect will be, among other things, that your shares will not be counted for purposes of determining whether a quorum is present at the extraordinary general meeting. If you are a shareholder of record and you attend the extraordinary general meeting and wish to vote in person, you may withdraw your proxy and vote in person.

TO EXERCISE YOUR REDEMPTION RIGHTS, YOU MUST DEMAND IN WRITING THAT YOUR PUBLIC SHARES ARE REDEEMED FOR A PRO RATA PORTION OF THE FUNDS HELD IN THE TRUST ACCOUNT AND TENDER YOUR SHARES TO SUPERNOVA’S TRANSFER AGENT AT LEAST TWO BUSINESS DAYS PRIOR TO THE VOTE AT THE EXTRAORDINARY GENERAL MEETING. IN ORDER TO EXERCISE YOUR REDEMPTION RIGHT, YOU NEED TO IDENTIFY YOURSELF AS A BENEFICIAL HOLDER AND PROVIDE YOUR LEGAL NAME, PHONE NUMBER AND ADDRESS IN YOUR WRITTEN DEMAND. THE DEPOSITORY TRUST COMPANY (“DTC”) WILL PROCESS THE REDEMPTION OFFER THROUGH DTC’S AUTOMATED TENDER OFFER PROGRAM (“ATOP”) UNTIL THE LATER OF THE OFFER’S EXPIRATION DATE OF AT 5PM EST, ANY EXTENSION OF SUCH EXPIRATION DATE OR THE END OF ANY PERIOD FOR DELIVERY OF SECURITIES PURSUANT TO NOTICES OF GUARANTEED DELIVERY. IF THE BUSINESS COMBINATION IS NOT COMPLETED, THEN THESE SHARES WILL BE RETURNED TO YOU OR YOUR ACCOUNT. IF YOU HOLD THE SHARES IN STREET NAME, YOU WILL NEED TO INSTRUCT THE ACCOUNT EXECUTIVE AT YOUR BANK OR BROKER TO WITHDRAW THE SHARES FROM YOUR ACCOUNT IN ORDER TO EXERCISE YOUR REDEMPTION RIGHTS.

On behalf of Supernova’s board of directors, we would like to thank you for your support and look forward to the successful completion of the Business Combination.

Sincerely,

Spencer M. Rascoff and Alexander M. Klabin

Co-Chairs

of the Board of Directors

The accompanying proxy statement/prospectus is dated , 2022, and is first being mailed to shareholders on or about , 2022.

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SUPERNOVA PARTNERS ACQUISITION COMPANY II, LTD.

4301 50th Street NW,

Suite 300 PMB 1044,

Washington, D.C. 20016

NOTICE OF EXTRAORDINARY GENERAL MEETING

TO BE HELD ON , 2022

TO THE SHAREHOLDERS OF SUPERNOVA PARTNERS ACQUISITION COMPANY II, LTD.:

NOTICE IS HEREBY GIVEN that an extraordinary general meeting (the “extraordinary general meeting”) of Supernova Partners Acquisition Company II, Ltd., a Cayman Islands exempted company (“Supernova”), will be held at , Eastern Time, on , 2022, at the offices of located at , and virtually via live webcast at , on such other date and at such other place to which the meeting may be adjourned. As all shareholders are no doubt aware, due to the current novel coronavirus

(“COVID-19”)

global pandemic, there are restrictions in place in many jurisdictions relating to the ability to conduct

in-person

meetings. As part of our precautions regarding

COVID-19,

we are planning for the possibility that the meeting may be held virtually over the internet, but the physical location of the meeting will remain at the location specified above for the purposes of our amended and restated memorandum and articles of association. You are cordially invited to attend the extraordinary general meeting, which will be held for the following purposes:

•

Proposal No. 1—The Business Combination Proposal

—

RESOLVED

, as an ordinary resolution, that Supernova’s entry into the Merger Agreement, dated as of October 6, 2021 (as may be amended, supplemented or otherwise modified from time to time, the “Merger Agreement”), by and among Supernova, Supernova Merger Sub, Inc., a Delaware corporation (“First Merger Sub”), Supernova Romeo Merger Sub, LLC, a Delaware limited liability company (“Second Merger Sub”) and Rigetti Holdings, Inc., a Delaware corporation (“Rigetti”), a copy of which is attached to the proxy statement/prospectus as Annex A, pursuant to which, among other things, following the

de-registration

of Supernova as an exempted company in the Cayman Islands and the continuation and domestication of Supernova as a corporation in the State of Delaware with the name “Rigetti Computing, Inc.” (the “Domestication”) (a) First Merger Sub will merge with and into Rigetti, with Rigetti surviving such merger as a wholly owned subsidiary of New Rigetti, followed by the Second Merger, whereby, immediately following and as part of the same overall transaction as the First Merger, Rigetti will merge with and into Second Merger Sub, with Second Merger Sub surviving such merger as a wholly owned subsidiary of New Rigetti and (b) at the Effective Time, each share of Rigetti outstanding as of immediately prior to the Effective Time will be exchanged for shares of New Rigetti Common Stock based on an implied Rigetti equity value of $1,041,000,000, and each Rigetti option or warrant will convert into options or warrants to purchase New Rigetti Common Stock and each Rigetti Restricted Stock Unit Award will convert into restricted stock units for New Rigetti Common Stock, certain related agreements (including the Subscription Agreements and the Registration Rights Agreement, each in the form attached to the proxy statement/prospectus as Annex E and Annex F, respectively), and the transactions contemplated thereby, be approved, ratified and confirmed in all respects.

•

Proposal No. 2—The Domestication Proposal

—

RESOLVED

, as a special resolution, that Supernova be transferred by way of continuation to Delaware pursuant to Article 47 of the amended and restated articles of association of Supernova, Part XII of the Companies Act (As Revised) of the Cayman Islands and Section 388 of the General Corporation Law of the State of Delaware and, immediately upon being

de-registered

in the Cayman Islands, Supernova be continued and domesticated as a corporation under the laws of the State of Delaware and, conditional upon, and with effect from, the registration of Supernova as a corporation in the State of Delaware, the name of Supernova be changed from “Supernova Partners Acquisition Company II, Ltd.” to “Rigetti Computing, Inc.”

•

Proposal No. 3—The Proposed Charter and Bylaws Proposal—RESOLVED

, as a special resolution, that the amended and restated memorandum and articles of association of Supernova currently in effect be

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amended and restated by the deletion in their entirety and substitution in their place with the certificate of incorporation and bylaws of Supernova (copies of which are attached to the proxy statement/prospectus as Annex C and Annex D, respectively), which be approved as the certificate of incorporation and bylaws of Rigetti Computing, Inc., effective upon the effectiveness of the Domestication.

•

Advisory Governing Documents Proposals

—to consider and vote upon the following four (4) separate resolutions, each as an ordinary resolution and on a

non-binding

advisory basis, to approve the following material differences between the amended and restated memorandum and articles of association of Supernova (“Existing Governing Documents”) and the proposed new certificate of incorporation, a copy of which is attached to the proxy statement/prospectus as Annex C (the “Proposed Certificate of Incorporation”) and the proposed new bylaws, a copy of which is attached to the proxy statement/prospectus as Annex D (the “Proposed Bylaws”) of “Rigetti Computing, Inc.” upon the Domestication (such proposals, collectively, the “Advisory Governing Documents Proposals”):

•

Proposal No. 4A—Advisory Governing Documents Proposal A—RESOLVED

, as an ordinary resolution, that the change in the authorized share capital of Supernova from (i) 500,000,000 Class A ordinary shares, par value $0.0001 per share, (ii) 50,000,000 Class B ordinary shares, par value $0.0001 per share and (iii) 5,000,000 preference shares, par value $0.0001 per share, to (a) 1,000,000,000 shares of common stock, par value $0.0001 per share, of New Rigetti and (b) 10,000,000 shares of preferred stock, par value $0.0001 per share, of New Rigetti be approved.

•

Proposal No. 4B—Advisory Governing Documents Proposal B—RESOLVED,

as an ordinary resolution, that the authorization to the board of directors of New Rigetti (the “New Rigetti Board”) to issue any or all shares of New Rigetti Preferred Stock in one or more classes or series, with such terms and conditions as may be expressly determined by the New Rigetti Board and as may be permitted by the Delaware General Corporation Law be approved.

•

Proposal No. 4C—Advisory Governing Documents Proposal C—RESOLVED,

as an ordinary resolution, that the removal of the ability of New Rigetti stockholders to take action by written consent in lieu of a meeting unless such action has been recommended or approved pursuant to a resolution approved by the affirmative vote of all of the directors then in office be approved.

•

Proposal No. 4D—Advisory Governing Documents Proposal D—RESOLVED,

as an ordinary resolution, that the amendment and restatement of the Existing Governing Documents be approved and that all other changes necessary or, as mutually agreed in good faith by Supernova and Rigetti, desirable in connection with the replacement of Existing Governing Documents with the Proposed Certificate of Incorporation and Proposed Bylaws as part of the Domestication (copies of which are attached to the proxy statement/prospectus as Annex C and Annex D, respectively), including (i) changing the post-Business Combination corporate name from “Supernova Partners Acquisition Company II, Ltd.” to “Rigetti Computing, Inc.” (which is expected to occur upon the consummation of the Domestication), (ii) making New Rigetti’s corporate existence perpetual, (iii) adopting Delaware as the exclusive forum for certain stockholder litigation and the United States District Court for the District of Delaware as the exclusive forum for litigation arising out of the Securities Act of 1933, as amended, and (iv) removing certain provisions related to our status as a blank check company that will no longer be applicable upon consummation of the Business Combination be approved.

•

Proposal No. 5—The Stock Issuance Proposal

—

RESOLVED

, as an ordinary resolution, that for the purposes of complying with the applicable provisions of Rule 312.03 of the New York Stock Exchange (“NYSE”) Listed Company Manual, the issuance of the shares of New Rigetti Common Stock be approved.

•

Proposal No.

6— The Director Election Proposal

—

RESOLVED,

as an ordinary resolution, that Chad Rigetti, Alissa Fitzgerald, Gen. Peter Pace, Ray Johnson, David Cowan, Cathy McCarthy, Michael Clifton and be elected to serve on the New Rigetti Board upon the consummation of the Business Combination.

•

Proposal No. 7—The Equity Incentive Plan Proposal

—

RESOLVED

, as an ordinary resolution, that the New Rigetti 2022 Equity Incentive Plan, a copy of which is attached to the proxy statement/prospectus as Annex H, be adopted and approved.

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•

Proposal No. 8—The Employee Stock Purchase Plan Proposal

—

RESOLVED

, as an ordinary resolution, that the New Rigetti Employee Stock Purchase Plan, a copy of which is attached to the proxy statement/prospectus as Annex I, be adopted and approved.

•

Proposal No. 9—The Adjournment Proposal

—

RESOLVED

, as an ordinary resolution, that the adjournment of the extraordinary general meeting to a later date or dates (i) to solicit additional proxies for the purpose of obtaining approval by the shareholders of Supernova for each of the proposals necessary to consummate transactions contemplated by the Merger Agreement, (ii) for the absence of a quorum or (iii) if the holders of the Class A ordinary shares have elected to redeem a number of Class A ordinary shares as of such time that would reasonably be expected to result in the conditions required for the Closing of the Merger Agreement not to be satisfied; provided that, without the consent of Rigetti, in no event shall the extraordinary general meeting of shareholders be adjourned to a date that is more than fifteen (15) business days later than the most recently adjourned meeting or to a date that five (5) business days prior to the termination date of the Merger Agreement, at the extraordinary general meeting be approved.

Each of the Business Combination Proposal, the Domestication Proposal, the Proposed Charter and Bylaws Proposal, the Stock Issuance Proposal, the Director Election Proposal, the Equity Incentive Plan Proposal and the Employee Stock Purchase Plan Proposal is conditioned on the approval and adoption of each of the other Condition Precedent Proposals. The Advisory Governing Documents Proposals are

non-binding

These items of business are described in this proxy statement/prospectus, which we encourage you to read carefully and in its entirety before voting.

Only holders of record of ordinary shares at the close of business on January 18, 2022 are entitled to notice of and to vote and have their votes counted at the extraordinary general meeting and any adjournment of the extraordinary general meeting.

This proxy statement/prospectus and accompanying proxy card is being provided to Supernova’s shareholders in connection with the solicitation of proxies to be voted at the extraordinary general meeting and at any adjournment of the extraordinary general meeting.

Whether or not you plan to attend the extraordinary general meeting, all of Supernova’s shareholders should read this proxy statement/prospectus, including the Annexes and the documents referred to herein carefully and in their entirety. You should also carefully consider the risk factors described in “

Risk Factors

”

beginning on page

59 of this proxy statement/prospectus.

After careful consideration, the board of directors of Supernova has unanimously approved the Merger Agreement and the transactions contemplated thereby, including the Merger, and unanimously recommends that shareholders vote “FOR” the adoption of the Merger Agreement and approval of the transactions contemplated thereby, including the Merger, and “FOR” all other proposals presented to Supernova’s shareholders in this proxy statement/prospectus. When you consider the recommendation of these proposals by the board of directors of Supernova, you should keep in mind that the Sponsor and Supernova’s directors and officers have interests in the Business Combination that may conflict with your interests as a shareholder. See the section entitled “

Business Combination Proposal—Interests of Supernova’s Sponsor, Directors and Executive Officers in the Business Combination

” in this proxy statement/prospectus for a further discussion of these considerations.

Pursuant to the Existing Governing Documents, a public shareholder may request of Supernova that New Rigetti redeem all or a portion of its public shares for cash if the Business Combination is consummated. As a holder of public shares, you will be entitled to receive cash for any public shares to be redeemed only if you:

(1) (a) hold public shares, or (b) if you hold public shares through units, elect to separate your units into the underlying public shares and warrants prior to exercising your redemption rights with respect to the public shares;

iii

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(2) submit a written request to AST, Supernova’s transfer agent, in which you (a) request that New Rigetti redeem all or a portion of your public shares for cash, and (b) identify yourself as the beneficial holder of the public shares and provide your legal name, phone number and address; and

(3) deliver share certificates (if any) and other redemption forms (as applicable) to AST, Supernova’s transfer agent, physically or electronically through The Depository Trust Company.

Holders must complete the procedures for electing to redeem their public shares in the manner described above prior to 5:00 p.m., Eastern Time, on , 2022 (two business days before the extraordinary general meeting) in order for their shares to be redeemed.

Holders of units must elect to separate the units into the underlying public shares and warrants prior to exercising redemption rights with respect to the public shares. If holders hold their units in an account at a brokerage firm or bank, holders must notify their broker or bank that they elect to separate the units into the underlying public shares and warrants, or if a holder holds units registered in its own name, the holder must contact AST, Supernova’s transfer agent, directly and instruct them to do so. The redemption rights include the requirement that a holder must identify itself in writing as a beneficial holder and provide its legal name, phone number and address to AST in order to validly redeem its shares. Public shareholders may elect to redeem public shares regardless of if or how they vote in respect of the Business Combination Proposal. If the Business Combination is not consummated, the public shares will be returned to the respective holder, broker or bank. If the Business Combination is consummated, and if a public shareholder properly exercises its right to redeem all or a portion of the public shares that it holds and timely delivers its share certificates (if any) and other redemption forms (as applicable) to AST, Supernova’s transfer agent, New Rigetti will redeem such public shares for a

per-share

price, payable in cash, equal to the pro rata portion of the trust account established at the consummation of Supernova’s initial public offering (the “trust account”), calculated as of two business days prior to the consummation of the Business Combination. For illustrative purposes, as of September 30, 2021, this would have amounted to approximately $10.00 per issued and outstanding public share. If a public shareholder exercises its redemption rights in full, then it will be electing to exchange its public shares for cash and will no longer own public shares. See “

Extraordinary General Meeting of Supernova—Redemption Rights

” in this proxy statement/prospectus for a detailed description of the procedures to be followed if you wish to redeem your public shares for cash.

Notwithstanding the foregoing, a public shareholder, together with any affiliate of such public shareholder or any other person with whom such public shareholder is acting in concert or as a “group” (as defined in Section 13(d)(3) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”)), will be restricted from redeeming its public shares with respect to more than an aggregate of 15% of the public shares. Accordingly, if a public shareholder, alone or acting in concert or as a group, seeks to redeem more than 15% of the public shares, then any such shares in excess of that 15% limit would not be redeemed for cash.

Supernova Partners II LLC, a Cayman Islands exempted company (the “Sponsor”) and each of our directors and officers (the “Initial Shareholders”) have, pursuant to the sponsor support agreement with the Sponsor, Rigetti and Supernova’s directors and officers (the “Sponsor Support Agreement”), agreed to, among other things, vote all of their ordinary shares in favor of the proposals being presented at the extraordinary general meeting and waive their anti-dilution rights with respect to their Class B ordinary shares in connection with the consummation of the Business Combination. Such shares will be excluded from the pro rata calculation used to determine the

per-share

redemption price. As of the date of this proxy statement/prospectus, the Initial Shareholders own approximately 20% of the issued and outstanding ordinary shares. See “

Business Combination Proposal—Related Agreements—Sponsor Support Agreement

” in the accompanying proxy statement/prospectus for more information related to the Sponsor Support Agreement.

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shares in an amount that would cause New Rigetti’s net tangible assets (as determined in accordance with

Rule 3a51-1(g)(1)

of the Exchange Act) to be less than $5,000,001 after giving effect to the transactions contemplated by the Merger Agreement and the PIPE Financing (as defined in the proxy statement/prospectus). Nor will Supernova redeem public shares in an amount that would cause the aggregate cash proceeds available for release from the trust account in connection with the transactions contemplated in the Merger Agreement (including the PIPE Financing) to be less than $165 million.

two-thirds

(2/3) of the ordinary shares who, being present in person or by proxy and entitled to vote at the extraordinary general meeting, vote at the extraordinary general meeting. The approval of each of the Business Combination Proposal, each of the Advisory Governing Documents Proposals, the Equity Incentive Plan Proposal, the Employee Stock Purchase Plan Proposal, the Stock Issuance Proposal, the Director Election Proposal and the Adjournment Proposal requires an ordinary resolution under Cayman Islands law, being the affirmative vote of a majority of the ordinary shares represented in person or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting. Because the Domestication Proposal involves a vote to continue Supernova outside the jurisdiction of the Cayman Islands, holders of Class B ordinary shares will have ten votes per Class B ordinary share and holders of Class A ordinary shares will have one vote per Class A ordinary share for purposes of the Domestication Proposal. Holders of Class B ordinary shares and Class A ordinary shares will have one vote per share on all other proposals.

Your vote is very important

. Whether or not you plan to attend the extraordinary general meeting, please vote as soon as possible by following the instructions in this proxy statement/prospectus to make sure that your shares are represented at the extraordinary general meeting. If you hold your shares in “street name” through a bank, broker or other nominee, you will need to follow the instructions provided to you by your bank, broker or other nominee to ensure that your shares are represented and voted at the extraordinary general meeting. The Business Combination will be consummated only if the Condition Precedent Proposals are approved at the extraordinary general meeting. Each of the Condition Precedent Proposals is cross-conditioned on the approval of each other. The Advisory Governing Documents Proposals are

non-binding

Your attention is directed to the remainder of the proxy statement/prospectus following this notice (including the Annexes and other documents referred to herein) for a more complete description of the proposed Business Combination and related transactions and each of the proposals. You are encouraged to read this proxy statement/prospectus carefully and in its entirety, including the Annexes and other documents referred to herein. If you have any questions or need assistance voting your ordinary shares, please contact Morrow Sodali LLC, our proxy solicitor, by calling (800)

662-5200,

or banks and brokers can call collect at (203)

658-9400,

or by emailing Supernova.info@investor.morrowsodali.com.

Thank you for your participation. We look forward to your continued support.

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By Order of the Board of Directors of Supernova Partners Acquisition Company II, Ltd.,

Spencer M. Rascoff and Alexander M. Klabin

Co-Chairs

of the Board of Directors

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TABLE OF CONTENTS


ADDITIONAL INFORMATION			1

TRADEMARKS			2

MARKET INDUSTRY AND OTHER DATA			2

SELECTED DEFINITIONS			3

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS			7

QUESTIONS AND ANSWERS FOR SHAREHOLDERS OF SUPERNOVA			9

SUMMARY OF THE PROXY STATEMENT/PROSPECTUS			31

SUMMARY UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION			55

COMPARATIVE HISTORICAL AND UNAUDITED PRO FORMA CONDENSED COMBINED PER SHARE FINANCIAL INFORMATION			57

RISK FACTORS			59

EXTRAORDINARY GENERAL MEETING OF SUPERNOVA			114

BUSINESS COMBINATION PROPOSAL			122

DOMESTICATION PROPOSAL			165

PROPOSED CHARTER AND BYLAWS PROPOSAL			168

ADVISORY GOVERNING DOCUMENTS PROPOSALS			169

ADVISORY GOVERNING DOCUMENTS PROPOSAL A—APPROVAL OF AUTHORIZATION OF CHANGE TO AUTHORIZED SHARE CAPITAL, AS SET FORTH IN THE PROPOSED GOVERNING DOCUMENTS			172

ADVISORY GOVERNING DOCUMENTS PROPOSAL B—APPROVAL OF PROPOSAL REGARDING ISSUANCE OF PREFERRED STOCK OF NEW RIGETTI AT THE BOARD OF DIRECTORS’ SOLE DISCRETION, AS SET FORTH IN THE PROPOSED GOVERNING DOCUMENTS			174

ADVISORY GOVERNING DOCUMENTS PROPOSAL C—APPROVAL OF PROPOSAL REGARDING THE ABILITY OF STOCKHOLDERS TO ACT BY WRITTEN CONSENT, AS SET FORTH IN THE PROPOSED GOVERNING DOCUMENTS			176

ADVISORY GOVERNING DOCUMENTS PROPOSAL D—APPROVAL OF OTHER CHANGES IN CONNECTION WITH ADOPTION OF THE PROPOSED GOVERNING DOCUMENTS			178

STOCK ISSUANCE PROPOSAL			181

DIRECTOR ELECTION PROPOSAL			183

THE EQUITY INCENTIVE PLAN PROPOSAL			185

THE EMPLOYEE STOCK PURCHASE PLAN PROPOSAL			194

ADJOURNMENT PROPOSAL			199

U.S. FEDERAL INCOME TAX CONSIDERATIONS			201

UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION			215

INFORMATION ABOUT SUPERNOVA			227

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SUPERNOVA’S MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS			238

INFORMATION ABOUT RIGETTI			242

RIGETTI’S MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS			262

RIGETTI’S EXECUTIVE AND DIRECTOR COMPENSATION			278

MANAGEMENT OF NEW RIGETTI FOLLOWING THE BUSINESS COMBINATION			290

BENEFICIAL OWNERSHIP OF SECURITIES			297

CERTAIN RELATIONSHIPS AND RELATED PERSON TRANSACTIONS			301

COMPARISON OF CORPORATE GOVERNANCE AND SHAREHOLDER RIGHTS			305

DESCRIPTION OF NEW RIGETTI SECURITIES			307

SECURITIES ACT RESTRICTIONS ON RESALE OF NEW RIGETTI COMMON STOCK			321

STOCKHOLDER PROPOSALS AND NOMINATIONS			323

SHAREHOLDER COMMUNICATIONS			324

LEGAL MATTERS			325

EXPERTS			325

DELIVERY OF DOCUMENTS TO SHAREHOLDERS			325

ENFORCEABILITY OF CIVIL LIABILITY			326

WHERE YOU CAN FIND MORE INFORMATION; INCORPORATION BY REFERENCE			326

INDEX TO FINANCIAL STATEMENTS			F-1

ANNEX A			A-1

ANNEX B			B-1

ANNEX C			C-1

ANNEX D			D-1

ANNEX E			E-1

ANNEX F			F-1

ANNEX G			G-1

ANNEX H			H-1

ANNEX I			I-1

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ADDITIONAL INFORMATION

This proxy statement/prospectus incorporates important business and financial information about Supernova and Rigetti that is not included in or delivered with the document. You may request copies of this proxy statement/prospectus and any other publicly available information concerning Supernova, without charge, by written request to Supernova Partners Acquisition Company II, Ltd., 4301 50th Street NW, Suite 300 PMB 1044, Washington, D.C. 20016, or by telephone request at

202-918-7050;

or Morrow Sodali LLC, our proxy solicitor, by calling (800)

662-5200,

or banks and brokers can call collect at (203)

658-9400,

or by emailing Supernova.info@investor.morrowsodali.com or from the SEC through the SEC website at http://www.sec.gov.

In order for Supernova’s shareholders to receive timely delivery of the documents in advance of the extraordinary general meeting of Supernova to be held on , 2022 you must request the information no later than five business days prior to the date of the extraordinary general meeting, by , 2022.

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TRADEMARKS

This document contains references to trademarks, trade names and service marks certain of which belong to Rigetti and others that are the property of other organizations. Solely for convenience, trademarks, trade names and service marks referred to in this proxy statement/prospectus may appear without the

or TM symbols, but such references are not intended to indicate, in any way, that the applicable licensor will not assert, to the fullest extent under applicable law, its rights to these trademarks and trade names. We do not intend our use or display of other companies’ trade names, trademarks or service marks to imply a relationship with, or endorsement or sponsorship of us by, any other companies.

MARKET INDUSTRY AND OTHER DATA

This proxy statement/prospectus includes industry and market data obtained from periodic industry publications, third-party studies and surveys, as well as from filings of public companies in our industry and internal company surveys. These sources include government and industry sources. Industry publications and surveys generally state that the information contained therein has been obtained from sources believed to be reliable. Although we believe the industry and market data to be reliable as of the date of this proxy statement/prospectus, this information could prove to be inaccurate. Industry and market data could be wrong because of the method by which sources obtained their data and because information cannot always be verified with complete certainty due to the limits on the availability and reliability of raw data, the voluntary nature of the data gathering process and other limitations and uncertainties. Each publication, study and report speaks as of its original publication date (and not as of the date of this proxy statement/prospectus). Certain of these publications, studies and reports were published before

the COVID-19 pandemic

and therefore do not reflect any impact

of COVID-19 on

any specific market or globally. In addition, we do not know all of the assumptions regarding general economic conditions or growth that were used in preparing the forecasts from the sources relied upon or cited herein. The industry in which we operate is subject to a high degree of uncertainty and risk due to a variety of factors, including those described in the section titled “Risk Factors.” These and other factors could cause results to differ materially from those expressed in these publications and reports.

The sources of certain statistical data, estimates, and forecasts contained in this prospectus are the following independent industry sources:

•

Analytics India Magazine,

Now GANs Are Being Used For Drug Discovery: Complete Guide To Quantum GAN With Python Code

, August 2021

•

Boston Consulting Group,

What Happens When ‘If’ Turns to ‘When’ in Quantum Computing?

, July 2021.

•

Boston Consulting Group,

Where Will Quantum Computers Create Value —and When?

, May 2019.

•

Emergen Research,

High-Performance Computing (HPC)

Market

, April 2021.

•

Fortune Business Insights,

Machine Learning (ML) Market Size, Share & Covid-19 Impact Analysis

, June 2021.

•

Gartner,

Gartner Forecasts Worldwide Public Cloud End-User Spending to Grow 23% in 2021

, April 2021.

•

Google AI Blog,

Quantum Machine Learning and the Power of Data

, June 2021.

•

Grand View Research,

High Performance Computing Market Size Worth $53.6 Billion By 2027

, September 2020.

•

Nature Communications,

Power of data in quantum machine learning

, May 2021.

•

Nature Communications,

The power of quantum neural networks

, June 2021.

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SELECTED DEFINITIONS

Unless otherwise stated in this proxy statement/prospectus or the context otherwise requires, references to:

“

Articles of Association

” are to the amended and restated articles of association of Supernova;

“

AST

” are to American Stock Transfer & Trust Company;

“

Business Combination

” are to the Domestication, the Merger and other transactions contemplated by the Merger Agreement, collectively, including the PIPE Financing;

“

Cayman Islands Companies Act

” are to the Companies Act (As Revised) of the Cayman Islands as the same may be amended from time to time;

“

Class

A ordinary shares

” are to the Class A ordinary shares, par value $0.0001 per share, of Supernova, which will automatically convert, on a

one-for-one

basis, into shares of New Rigetti Common Stock in connection with the Domestication;

“

Class

B ordinary shares

” are to the 8,625,000 Class B ordinary shares, par value $0.0001 per share, of Supernova outstanding as of the date of this proxy statement/prospectus that were initially issued to our Sponsor in a private placement prior to our initial public offering and of which 34,500 were transferred to each of the Supernova independent directors in February 2021, and, in connection with the Domestication, will automatically convert, on a

one-for-one

basis, into shares of New Rigetti Common Stock;

“

Closing

” are to the closing of the Business Combination;

“

Closing Date

” are to the date on which the Closing actually occurs;

“

Condition Precedent Proposals

” are to the Business Combination Proposal, the Domestication Proposal, the Proposed Charter and Bylaws Proposal, the Stock Issuance Proposal, the Director Election Proposal, the Equity Incentive Plan Proposal and the Employee Stock Purchase Plan Proposal, collectively;

“

Domestication

” are to the transfer by way of continuation and deregistration of Supernova from the Cayman Islands and the continuation and domestication of Supernova as a corporation incorporated in the State of Delaware;

“

Effective Tim

e” are to the time at which the Merger becomes effective;

“

Employee Stock Purchase Plan

” are to the New Rigetti 2021 Employee Stock Purchase Plan to be considered for adoption and approval by the shareholders pursuant to the Employee Stock Purchase Plan Proposal;

“

extraordinary general meeting

” are to the extraordinary general meeting of Supernova at , on , 2022, located at , and virtually via live webcast at , or at such other time, on such other date and at such other place to which the meeting may be adjourned;

“

Existing Governing Documents

” are to the Memorandum of Association and the Articles of Association;

“

Founder Shares

” are to Class B ordinary shares initially issued to the Sponsor in a private placement prior to Supernova’s initial public offering and the Class A ordinary shares that will be issued upon the automatic conversion of the Class B ordinary shares at the time of our initial business combination or earlier at the option of the holders thereof;

“

GAAP

” are to generally accepted accounting principles in the United States, as applied on a consistent basis;

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“

initial public offering

” are to Supernova’s initial public offering that was consummated on March 4, 2021;

“

Incentive Equity Plan

” are to the New Rigetti 2022 Equity Incentive Plan to be considered for adoption and approval by the shareholders pursuant to the Equity Incentive Plan Proposal;

“

Initial Shareholders

” are to Sponsor and each of the directors and officers of Supernova;

“

Memorandum of Association

” are to the amended and restated memorandum of association of Supernova;

“

Merger

” are to the merger of First Merger Sub with and into Rigetti pursuant to the Merger Agreement, with Rigetti as the surviving company in the Merger and the merger of Rigetti with and into Second Merger Sub, with Second Merger Sub being the surviving entity in the merger, and after giving effect to such Merger, Rigetti becoming a wholly owned subsidiary of New Rigetti;

“

Merger Agreement

” are to that certain Merger Agreement, dated October 6, 2021, by and among Supernova, Supernova Merger Sub, Inc., Supernova Romeo Merger Sub, LLC and Rigetti, and as may be amended, supplemented or otherwise modified from time to time;

“

Nasdaq

” are to The NASDAQ Capital Market.

“

New Rigetti

” are to Rigetti Computing, Inc., a Delaware corporation, upon and after the Domestication and the consummation of the Business Combination;

“

New Rigetti Board

” or “

New Rigetti’s

Board

” are to the board of directors of New Rigetti;

“

New Rigetti Common Stock

” are to the common stock, par value $0.0001 per share, of New Rigetti;

“

New Rigetti Preferred Stock

” are to the preferred stock, par value $0.0001 per share, of New Rigetti;

“

NYSE

” are to the New York Stock Exchange;

“

ordinary shares

” are to our Class A ordinary shares and our Class B ordinary shares;

“

PIPE Financing

” are to the transactions contemplated by the Subscription Agreements, pursuant to which the PIPE Investors have collectively committed to subscribe for an aggregate of 14,641,244 shares of New Rigetti Common Stock for an aggregate purchase price of $147,510,000 to be consummated in connection with Closing;

“

private placement warrants

” are to the 4,450,000 private placement warrants outstanding as of the date of this proxy statement/ prospectus that were issued to our Sponsor as part of the closing of our initial public offering, which are substantially identical to the public warrants sold as part of the units in the initial public offering, subject to certain limited exceptions;

“

pro forma

” are to giving pro forma effect to the Business Combination, including the Merger and the PIPE Financing;

“

Proposed Bylaws

” are to the proposed bylaws of New Rigetti to be effective upon the Domestication attached to this proxy statement/prospectus as Annex D;

“

Proposed Certificate of Incorporation

” or “

Proposed Charter

” are to the proposed certificate of incorporation of New Rigetti to be effective upon the Domestication attached to this proxy statement/prospectus as Annex C;

“

Proposed Governing Documents

” are to the Proposed Certificate of Incorporation and the Proposed Bylaws;

“

public shareholders

” are to holders of public shares, whether acquired in Supernova’s initial public offering or acquired in the secondary market;

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“

public shares

” are to the currently outstanding 34,500,000 Class A ordinary shares of Supernova, whether acquired in Supernova’s initial public offering or acquired in the secondary market;

“

public warrants

” are to the currently outstanding 8,625,000 redeemable warrants to purchase Class A ordinary shares of Supernova that were issued by Supernova in its initial public offering;

“

redemption

” are to each redemption of public shares for cash pursuant to the Existing Governing Documents;

“

Registration Statement

” are to the registration statement of which this proxy statement/prospectus forms a part;

“

Rigetti

” are to Rigetti Holdings, Inc., a Delaware corporation, and its consolidated subsidiaries since the consummation of the Rigetti Holding Company Reorganization on October 5, 2021 and prior to the consummation of the Business Combination, and to Rigetti & Co, Inc. and its consolidated subsidiaries prior to the consummation of the Rigetti Holding Company Reorganization on October 5, 2021;

“

Rigetti Common Stock

” means the shares of common stock, par value $0.000001 per share, of Rigetti, which shares have been designated as Class A Common Stock and the shares of common stock, par value $0.000001 per share, of Rigetti, which shares have been designated as Class B Common Stock;

“

Rigetti Holding Company Reorganization

” means the holding company reorganization pursuant to which (i) Rigetti & Co, Inc. established Rigetti Holdings, Inc. and Rigetti Intermediate Merger Sub Inc., each as wholly owned subsidiaries of Rigetti & Co, Inc., (ii) on October 5, 2021, pursuant to an Agreement and Plan of Merger (the “Holding Company Merger Agreement”) by and among Rigetti & Co, Inc., Rigetti Holdings, Inc. and Rigetti Intermediate Merger Sub, Inc., dated as of October 5, 2021, Rigetti Intermediate Merger Sub, Inc. merged with and into Rigetti & Co, Inc., with Rigetti & Co, Inc. surviving such merger as a wholly owned subsidiary of Rigetti Holdings, Inc., with all of the outstanding equity securities of Rigetti & Co, Inc. exchanged for identical equity securities of Rigetti Holdings, Inc. and (iii) on October 6, Rigetti & Co, Inc. was converted into a Delaware limited liability company and continues as “Rigetti & Co, LLC”;

“

Rigetti Preferred Stock

” means, collectively, the shares of preferred stock, par value $0.000001 per share, of Rigetti, of which shares have been designated as Series C Preferred Stock and Series

C-1

Preferred Stock;

“

Rigetti Restricted Stock Unit Awards

” means an award of restricted stock units based on shares of Rigetti Common Stock (whether to be settled in cash or shares), granted under the 2013 Plan;

“

Rigetti Stockholders

” are the current and former holders of Rigetti shares prior to the consummation of the Business Combination;

“

Rigetti Stockholder Approval

” means the approval of the Merger Agreement and the Transactions, including the Mergers and the making of any filings, notices or information statements in connection with the foregoing, in accordance with the terms and subject to the conditions of Rigetti’s governing documents and applicable law;

“

SEC

” are to the Securities and Exchange Commission;

“

Securities Act

” are to the Securities Act of 1933, as amended;

“

Sponsor

” are to Supernova Partners II LLC, a Cayman Islands exempted company;

“

Sponsor Support Agreement

” are to are to that certain Sponsor Agreement, dated as of October 6, 2021, by and among the Sponsor, Supernova and Rigetti, as amended and modified from time to time;

“

Subscription Agreements

” are to the subscription agreements, entered into by Supernova and each of the PIPE Investors in connection with the PIPE Financing;

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“

Supernova

,” “

” or “

our

” are to Supernova Partners Acquisition Company II, Ltd., a Cayman Islands exempted company, prior to the consummation of the Business Combination;

“

Supernova Board

” or “

our Board

” are to Supernova’s board of directors;

“

Supernova Insiders

” are Supernova’s officers, directors and Sponsor.

“

transfer agent

” are to AST, Supernova’s transfer agent;

“

trust account

” are to the trust account established at the consummation of Supernova’s initial public offering that holds the proceeds of the initial public offering and is maintained by AST, acting as trustee;

“

units

” are to the units of Supernova, each unit representing one Class A ordinary share and

one-fourth

of one warrant to acquire one Class A ordinary share, that were offered and sold by Supernova in its initial public offering and in its concurrent private placement; and

“

warrants

” are to the public warrants and the private placement warrants.

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CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

Certain statements in this proxy statement/prospectus may constitute “forward-looking statements” for purposes of the federal securities laws. Our forward-looking statements include, but are not limited to, statements regarding our or our management team’s expectations, hopes, beliefs, intentions or strategies regarding the future, including those relating to the Business Combination. The information included in this proxy statement/prospectus in relation to Rigetti has been provided by Rigetti and its management, and forward-looking statements include statements relating to our and its respective management team’s expectations, hopes, beliefs, intentions or strategies regarding the future, including those relating to the Business Combination, future financial performance and business strategies and expectations for its business. In addition, any statements that refer to projections, forecasts or other characterizations of future events or circumstances, including any underlying assumptions, are forward-looking statements. The words “anticipate,” “believe,” “contemplate,” “continue,” “could,” “estimate,” “expect,” “intends,” “may,” “might,” “plan,” “possible,” “potential,” “predict,” “project,” “should,” “will,” “would” and similar expressions may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. Forward-looking statements in this proxy statement/prospectus include, for example, statements about:

•

Rigetti’s ability to execute its business strategy, including monetization of its products;

•

our ability to complete the Business Combination with Rigetti or, if we do not consummate such Business Combination, any other initial business combination;

•

satisfaction or waiver of the conditions to the Business Combination including, among others: (i) approval by Supernova’s and Rigetti’s respective stockholders, (ii) the expiration or termination of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the “HSR Act”), and the obtaining of any consents required under antitrust laws in the jurisdictions specified on a schedule, (iii) no law or order enjoining or prohibiting the consummation of the Transactions being in force, (iv) Supernova having at least $5,000,001 of net tangible assets as of the Closing, (v) receipt of approval for listing on the New York Stock Exchange of the shares of New Rigetti Common Stock to be issued in connection with the Transactions, (vi) completion of the Domestication, (vii) the effectiveness of this registration statement

on Form S-4, (viii)

the accuracy of the parties’ respective representations and warranties (subject to specified materiality thresholds) and the material performance of the parties’ respective covenants and other obligations, (ix) no material adverse effect on Rigetti having occurred since signing that is continuing at Closing and (x) solely as relates to Rigetti’s obligation to consummate the Transaction, Supernova having at least $165,000,000 of available cash at the Closing;

•

the projected financial information, growth rate and market opportunity of New Rigetti;

•

the ability to obtain and/or maintain the listing of the New Rigetti Common Stock and the warrants on Nasdaq, and the potential liquidity and trading of such securities;

•

the risk that the proposed Business Combination disrupts current plans and operations of Rigetti as a result of the announcement and consummation of the proposed Business Combination;

•

the ability to recognize the anticipated benefits of the proposed Business Combination, which may be affected by, among other things, competition, the ability of the New Rigetti to grow and retain its key employees;

•

costs related to the proposed Business Combination;

•

changes in applicable laws or regulations;

•

our ability to raise financing in the future and ability to continue as a going concern;

•

our success in retaining or recruiting, or changes required in, our officers, key employees or directors following the completion of the Business Combination;

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•

our officers and directors allocating their time to other businesses and potentially having conflicts of interest with our business or in approving the Business Combination;

•

Rigetti’s estimates regarding expenses, future revenue, capital requirements and needs for additional financing;

•

Rigetti’s financial performance;

•

the ability of New Rigetti to expand or maintain its existing customer base; and

•

the effect of

COVID-19

on the foregoing, including our ability to consummate the Business Combination due to the uncertainty resulting from the recent

COVID-19

pandemic.

The forward-looking statements contained in this proxy statement/prospectus are based on current expectations and beliefs concerning future developments and their potential effects on us and/or Rigetti. There can be no assurance that future developments affecting us and/or Rigetti will be those that we and/or the Rigetti have anticipated. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond our control or the control of Rigetti) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not limited to, those factors described under the heading “

Risk Factors.

” Should one or more of these risks or uncertainties materialize, or should any of our assumptions prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements. Some of these risks and uncertainties may in the future be amplified by the

COVID-19

outbreak and there may be additional risks that we consider immaterial or which are unknown. It is not possible to predict or identify all such risks. Neither we nor Rigetti undertake any obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

Before any shareholder grants its proxy or instructs how its vote should be cast or vote on the proposals to be put to the extraordinary general meeting, such shareholder should be aware that the occurrence of the events described in the “

Risk Factors

” section and elsewhere in this proxy statement/prospectus may adversely affect us.

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QUESTIONS AND ANSWERS FOR SHAREHOLDERS OF SUPERNOVA

The questions and answers below highlight only selected information from this document and only briefly address some commonly asked questions about the proposals to be presented at the extraordinary general meeting, including with respect to the proposed Business Combination. The following questions and answers do not include all the information that is important to Supernova’s shareholders. Shareholders should read this proxy statement/prospectus, including the Annexes and the other documents referred to herein, carefully and in their entirety to fully understand the proposed Business Combination and the voting procedures for the extraordinary general meeting, which will be held at , Eastern Time, on , 2022, at the offices of located at , or virtually via live webcast at .

Q: Why am I receiving this proxy statement/prospectus?

Supernova shareholders are being asked to consider and vote upon, among other proposals, a proposal to approve and adopt the Merger Agreement and approve the transactions contemplated thereby, including the Business Combination. In accordance with the terms and subject to the conditions of the Merger Agreement, among other things, in connection with the Domestication, immediately prior to (but no later than the day preceding) the Closing Date, (i) Supernova will be renamed “Rigetti Computing, Inc.,” and (ii) each share of Rigetti outstanding as of immediately prior to the Effective Time will be exchanged for shares of New Rigetti Common Stock based on an implied equity value of $1,041,000,000 each Rigetti option or warrant will convert into options or warrants to purchase New Rigetti Common Stock and each Rigetti Restricted Stock Unit Award will convert into restricted stock units for New Rigetti Common Stock. See “

Business Combination Proposal

.”

A copy of the Merger Agreement is attached to this proxy statement/prospectus as Annex A and you are encouraged to read the Merger Agreement in its entirety.

The approval of each of the Business Combination Proposal, each of the Advisory Governing Documents Proposals, the Equity Incentive Plan Proposal, the Employee Stock Purchase Plan Proposal, the Stock Issuance Proposal, the Director Election Proposal and the Adjournment Proposal requires an ordinary resolution under Cayman Islands law, being the affirmative vote of a majority of the ordinary shares represented in person or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting, and each of the Domestication Proposal, and the proposal to approve by special resolution the adoption and approval of the proposed new certificate of incorporation and proposed new bylaws of New Rigetti (the “Proposed Charter and Bylaws Proposal”) requires a special resolution under Cayman Islands law, being the affirmative vote of the holders of at least

two-thirds

(2/3) of the ordinary shares who, being present in person or by proxy and entitled to vote at the extraordinary general meeting and, vote at the extraordinary general meeting. Because the Domestication Proposal involves a vote to continue Supernova outside the jurisdiction of the Cayman Islands, holders of Class B ordinary shares will have ten votes per Class B ordinary share and holders of Class A ordinary shares will have one vote per Class A ordinary share for purposes of the Domestication Proposal. Holders of Class B ordinary shares and Class A ordinary shares shall have one vote per share on all other proposals.

In connection with the Domestication, immediately prior to (but no later than the day preceding) the Closing Date: (i) each issued and outstanding Class A ordinary share and each issued and outstanding Class B ordinary share, of Supernova will be converted into one share of common stock, par value $0.0001 per share, of New Rigetti; (ii) each issued and outstanding whole warrant to purchase Class A ordinary shares of Supernova will automatically represent the right to purchase one share of New Rigetti Common Stock at an exercise price of $11.50 per share on the terms and conditions set forth in the Supernova warrant agreement; (iii) the governing documents of Supernova will be amended and restated and become the certificate of incorporation and the bylaws of New Rigetti as described in this proxy statement/prospectus; and (iv) Supernova’s name will change to “Rigetti Computing, Inc.” In connection with clauses (i) and (ii) of this paragraph, each issued and outstanding unit of Supernova that has not been previously separated into the underlying Class A ordinary shares of Supernova and the underlying warrants of Supernova prior to the Domestication will be cancelled and will entitle the holder thereof to one share of New Rigetti Common Stock and

one-fourth

of one warrant representing the

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right to purchase one share of New Rigetti Common Stock at an exercise price of $11.50 per share on the terms and subject to the conditions set forth in the Supernova warrant agreement. See “

Domestication Proposal

.”

The provisions of the Proposed Governing Documents will differ in certain material respects from the Existing Governing Documents. Please see “

What amendments will be made to the current constitutional documents of Supernova?

” below.

THE VOTE OF SHAREHOLDERS IS IMPORTANT. SHAREHOLDERS ARE ENCOURAGED TO VOTE AS SOON AS POSSIBLE AFTER CAREFULLY REVIEWING THIS PROXY STATEMENT/PROSPECTUS.

Q: What proposals are shareholders of Supernova being asked to vote upon?

At the extraordinary general meeting, Supernova is asking holders of its ordinary shares to consider and vote upon twelve (12) separate proposals:

•

a proposal to approve by ordinary resolution and adopt the Merger Agreement, including the Merger, and the transactions contemplated thereby;

•

a proposal to approve by special resolution the Domestication;

•

a proposal to approve by special resolution the Proposed Charter and Bylaws Proposal;

•

the following four (4) separate proposals, on a

non-binding

advisory basis, to approve by ordinary resolution the following material differences between the Existing Governing Documents and the Proposed Governing Documents:

•

to authorize the change in the authorized share capital of Supernova from (i) 500,000,000 Class A ordinary shares, par value $0.0001 per share, 50,000,000 Class B ordinary shares, par value $0.0001 per share, and 5,000,000 preference shares, par value $0.0001 per share, to (ii) 1,000,000,000 shares of New Rigetti Common Stock and 10,000,000 shares of New Rigetti Preferred Stock;

•

to authorize the New Rigetti Board to issue any or all shares of New Rigetti Preferred Stock in one or more classes or series, with such terms and conditions as may be expressly determined by the New Rigetti Board and as may be permitted by the DGCL;

•

to authorize the removal of the ability of New Rigetti stockholders to take action by written consent in lieu of a meeting unless such action has been recommended or approved pursuant to a resolution approved by the affirmative vote of all of the directors then in office;

•

to amend and restate the Existing Governing Documents and authorize all other changes necessary or, as mutually agreed in good faith by Supernova and Rigetti, desirable in connection with the replacement of Existing Governing Documents with the Proposed Governing Documents as part of the Domestication;

•

a proposal to approve by ordinary resolution the election of eight directors to serve staggered terms, who, upon consummation of the Business Combination, will be the directors of New Rigetti;

•

a proposal to approve by ordinary resolution shares of New Rigetti Common Stock in connection with the Business Combination and the PIPE Financing in compliance with the Rules of the NYSE Listed Company Manual;

•

a proposal to approve and adopt by ordinary resolution the Incentive Equity Plan;

•

a proposal to approve and adopt by ordinary resolution the Employee Stock Purchase Plan; and

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•

a proposal to approve by ordinary resolution the adjournment of the extraordinary general meeting to a later date or dates, if necessary, to, among other things, permit further solicitation and vote of proxies in the event that there are insufficient votes for the approval of one or more proposals at the extraordinary general meeting.

If our shareholders do not approve each of the Condition Precedent Proposals, then unless certain conditions in the Merger Agreement are waived by the applicable parties to the Merger Agreement, the Merger Agreement could terminate and the Business Combination may not be consummated.

For more information, please see “

Business Combination Proposal

,” “

Domestication Proposal

,” “

Proposed Charter and Bylaws Proposal

,” “

Advisory Governing Documents Proposals

,” “

Stock Issuance Proposal

,” “

Director Election Proposal

,” “

Equity Incentive Plan Proposal

,” “

Employee Stock Purchase Plan Proposal

” and “

Adjournment Proposal

.”

Supernova will hold the extraordinary general meeting to consider and vote upon these proposals. This proxy statement/prospectus contains important information about the Business Combination and the other matters to be acted upon at the extraordinary general meeting. Shareholders of Supernova should read it carefully.

After careful consideration, the Supernova Board has determined that the Business Combination Proposal, the Domestication Proposal, the Proposed Charter and Bylaws Proposal, each of the Advisory Governing Documents Proposals, the Stock Issuance Proposal, the Director Election Proposal, the Equity Incentive Plan Proposal, the Employee Stock Purchase Plan Proposal, and the Adjournment Proposal are in the best interests of Supernova and its shareholders and unanimously recommends that you vote or give instruction to vote “FOR” each of those proposals.

The existence of financial and personal interests of one or more of Supernova’s directors results in conflicts of interest on the part of such director(s) between what he, she or they may believe is in the best interests of Supernova and its shareholders and what he, she or they may believe is best for himself, herself or themselves in determining to recommend that shareholders vote for the proposals. In addition, the Sponsor and Supernova’s officers have interests in the Business Combination that may conflict with your interests as a shareholder. See the section entitled “

Business Combination Proposal—Interests of Supernova’s Sponsor, Directors and Executive Officers in the Business Combination

” for a further discussion of these considerations.

Q: Why is Supernova proposing the Business Combination?

Supernova is a blank check company that was incorporated on December 22, 2020 as a Cayman Islands exempted company for the purpose of effecting a merger, share exchange, asset acquisition, share purchase, reorganization or similar business combination with one or more businesses. Although Supernova may pursue an acquisition opportunity in any business, industry, sector or geographical location, for purposes of consummating the initial business combination, Supernova has focused on the technology industry. Supernova is not permitted under its Existing Governing Documents to effect a business combination with a blank check company or a similar type of company with nominal operations.

Supernova has identified several criteria and guidelines it believes are important for evaluating acquisition opportunities. Supernova has sought to acquire companies that meet its core investment philosophy, including companies that demonstrate sustainable competitive differentiation, have topline growth potential, a management team with a proven track record of success and a large addressable market.

Based on its due diligence investigations of Rigetti and the industry in which it operates, including the financial and other information provided by Rigetti in the course of negotiations, the Supernova Board believes that Rigetti is an attractive target based on its evaluation of Rigetti in light of the criteria and guidelines listed above. Further, based on its due diligence investigations of Rigetti and the industry in which it operates, including the

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financial and other information provided by Rigetti in the course of negotiations, the Supernova Board believes that the Business Combination with Rigetti presents an attractive business combination opportunity and is in the best interests of Supernova and its shareholders. The Supernova Board did consider certain potentially material negative factors in arriving at that conclusion. These factors are discussed in greater detail in the sections entitled “

Business

Combination Proposal—The Supernova Board’s Reasons for the Business Combination

” and “

Risk Factors—Risks Related to Supernova’s Business and to New Rigetti’s Business Following the Business Combination

.”

Q: Did the Supernova Board obtain a third-party valuation or fairness opinion in determining whether or not to proceed with the Business Combination?

No. The Supernova Board did not obtain a third-party valuation or fairness opinion in connection with its determination to approve the Business Combination. However, Supernova’s management, the members of the Supernova Board and the other representatives of Supernova have substantial experience in evaluating the operating and financial merits of companies similar to Rigetti and reviewed certain financial information of Rigetti and compared it to certain publicly traded companies, selected based on the experience and the professional judgment of Supernova’s management team, which enabled them to make the necessary analyses and determinations regarding the Business Combination. Accordingly, investors will be relying solely on the judgment of the Supernova Board in valuing Rigetti’s business and assuming the risk that the Supernova Board may not have properly valued such business.

Q: What will Rigetti’s equityholders receive in return for the Business Combination with Supernova?

On the Closing Date, First Merger Sub will merge with and into Rigetti, with Rigetti being the surviving entity in the merger, and immediately following the First Merger, Rigetti will merge with and into Second Merger Sub, with Second Merger Sub being the surviving entity in the merger. In connection with the Closing, Supernova will change its name to “Rigetti Computing, Inc.” In accordance with the terms and subject to the conditions of the Merger Agreement, at the Effective Time, each share of Rigetti outstanding as of immediately prior to the Effective Time will be exchanged for shares of New Rigetti Common Stock based on an implied Rigetti equity value of $1,041,000,000 each Rigetti option or warrant will convert into options or warrants to purchase New Rigetti Common Stock and each Rigetti Restricted Stock Unit Award will convert into restricted stock units for New Rigetti Common Stock.

Based on our current estimate, Rigetti’s existing stockholders are expected to receive approximately 78,153,546 shares of New Rigetti Common Stock, Rigetti’s existing optionholders are expected to receive approximately options to purchase 12,261,219 shares of New Rigetti Common Stock, Rigetti’s existing warrant holders are expected to receive approximately warrants to purchase 8,960,551 shares of New Rigetti Common Stock and holders of Rigetti Restricted Stock Unit Awards are expected to receive restricted stock units to be settled for approximately 5,551,897 shares of New Rigetti Common Stock. The value of the aggregate equity consideration to be paid to Rigetti’s equityholders in the Transactions will be equal to (i) $1,041,000,000 plus (ii) the aggregate exercise price of in the money Rigetti Warrants and Rigetti Options, in each case, outstanding prior to the effective time of the First Merger (the “Aggregate Equity Value”). At the Closing, each share of common stock and preferred stock of Rigetti that is issued and outstanding immediately prior to the effective time of the First Merger (other than “Excluded Shares,” as defined in the Merger Agreement) will be cancelled and converted into the right to receive a number of shares of New Rigetti Common Stock equal to an exchange ratio determined by dividing (a) the Aggregate Equity Value by (b) the “Aggregate Fully Diluted Company Common Stock” (as defined in the Merger Agreement), and then dividing that quotient by $10.00. As of October 31, 2021 and December 31, 2021, the Exchange Ratio is equal to 0.8182 and 0.8175, respectively. The exchange ratio and the number of shares to be issued to Rigetti’s existing equityholders will not change based on the number amount of redemptions from public SPAC investors.

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Q: How was the implied Rigetti equity value determined?

The implied Rigetti equity value of $1,041,000,000 plus the aggregate exercise price of in the money Rigetti Warrants and Rigetti Options, in each case, outstanding prior to the effective time of the First Merger, was determined based on an implied pro forma enterprise value of New Rigetti of approximately $1,152,000,000, including the anticipated $147,510,000 in PIPE Financing. As shown in the table below, the enterprise value was increased by estimated pro forma cash of approximately $434,000,000, which yields an equity value of approximately $1,586,000,000. The implied equity value of Rigetti of $1,041,000,000 represents the portion of the $1,586,000,000 pro forma equity value attributable to existing Rigetti equityholders after taking into account 34,500,000 Class A ordinary shares held by existing Supernova shareholders, 6,146,000 Class B ordinary shares not subject to forfeiture and 14,641,244 shares of New Rigetti Common Stock to be issued in the PIPE Financing.


	(amounts in millions, except per share amount)
Enterprise Value	$	1,152

Plus: Cash	$	434

Equity Value	$	1,586
Price Per Share	$	10.00

Shares Outstanding		133,441

Less: Class A Ordinary Shares		34,500
Less: Class B Ordinary Shares Not Subject to Forfeiture		6,146
Less: PIPE Financing Shares		14,641

Shares to Existing Rigetti Equityholders		78,153

Q: How will New Rigetti be managed following the Business Combination?

Following the Closing, it is expected that the New Rigetti Board will consist of eight directors. Please see the section entitled “

Management of New Rigetti Following the Business Combination

” for further information.

Q: What equity stake will current Supernova shareholders and current equity holders of Rigetti hold in New Rigetti immediately after the consummation of the Business Combination?

As of the date of this proxy statement/prospectus, there are (i) 34,500,000 Class A ordinary shares outstanding underlying units issued in Supernova’s initial public offering, and (ii) 8,625,000 Class B ordinary shares outstanding held by Supernova’s Initial Shareholders. As of the date of this proxy statement/prospectus, there are outstanding 4,450,000 private placement warrants held by the Sponsor and 8,625,000 public warrants. Each whole warrant entitles the holder thereof to purchase one Class A ordinary share and, following the Domestication, will entitle the holder thereof to purchase one share of New Rigetti Common Stock. Therefore, as of the date of this proxy statement/prospectus (without giving effect to the Business Combination or the PIPE Financing and assuming that none of Supernova’s outstanding public shares are redeemed in connection with the Business Combination), Supernova’s fully diluted share capital, giving effect to the exercise of all of the private placement warrants and public warrants, would be 56,200,000 ordinary shares.

The following table illustrates varying ownership levels in New Rigetti Common Stock immediately following the consummation of the Business Combination (assuming Closing occurred on October 31, 2021 and an Exchange Ratio as of October 31, 2021 of 0.8182) based on the varying levels of redemptions by the public shareholders and the following additional assumptions: (i) 78,153,546 shares of New Rigetti Common Stock are issued to the holders of shares of common stock and preferred stock of Rigetti at Closing, which would be the number of shares of New Rigetti Common Stock issued to these holders if Closing had occurred on October 31, 2021; (ii) 14,641,244 shares of New Rigetti Common Stock are issued in the PIPE Financing;

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(iii) no public warrants or private placement warrants to purchase New Rigetti Common Stock that will be outstanding immediately following Closing have been exercised; and (iv) no vested and unvested options or warrants to purchase shares of New Rigetti Common Stock that will be held by equityholders of Rigetti immediately following the Closing have been exercised and no restricted stock units have vested.


	Share Ownership in New Rigetti
	Assuming No Redemptions					Assuming 50% Redemptions					Assuming Maximum Redemptions					Assuming 100% Redemptions
	Shares		Percentage			Shares		Percentage			Shares		Percentage			Shares		Percentage
Former Rigetti equityholders		78,153,546		58.5	%		78,153,546		65.9	%		78,153,546		75.5	%		78,153,546		79.8	%
Sponsor		6,146,000		4.6	%		5,869,004		4.9	%		5,342,007		5.2	%		5,146,000		5.3	%
Former Supernova Class A stockholders		34,500,000		25.9	%		19,954,903		16.8	%		5,409,805		5.2	%		—		0.0	%
PIPE Investors		14,641,244		11.0	%		14,641,244		12.4	%		14,641,244		14.1	%		14,641,244		14.9	%

Total ownership		133,440,790		100.0	%		118,618,697		100.0	%		103,546,602		100.0	%		97,940,790		100.0	%

(1)

Assumes that approximately 84.3% of Supernova’s outstanding public shares are redeemed in connection with the Business Combination, which is the maximum amount of redemptions permitted while still satisfying the minimum cash condition to the consummation of the Business Combination in the Merger Agreement.

(2)

Excludes (i) the Sponsor Earn Out Shares that are subject to forfeiture and (ii) shares purchased by the Sponsor in the PIPE Financing. Includes up to 1,000,000 in Sponsor

Redemption-Based

Vesting Shares. As part of the Sponsor Support Agreement, the Sponsor has agreed that an amount of Class B ordinary shares based upon redemption levels will be forfeited if the New Rigetti Common Stock does not meet certain price thresholds post-closing. Up to 3,479,000 Sponsor Earn Out Shares may vest post-closing upon certain price thresholds. For additional information, see “Business Combination Proposal—Related Agreements—Sponsor Support Agreement.”

(3)

Amount shown represents share redemption levels reflecting 50% of the Max Permitted Redemption scenario (approximately 42.15% redemptions).

(4)

Assumes Rigetti and the PIPE Investors waive the minimum cash condition in the Merger Agreement. If all 34,500,000 Supernova Class A ordinary shares are redeemed, Supernova and Rigetti would be required to waive the minimum cash condition or otherwise obtain alternative financing arrangements to satisfy this Closing Condition. Additionally, waiver of the minimum cash condition in the Merger Agreement requires the consent of a majority of PIPE Investors (based on commitments), thus the above table assumes PIPE Investors have provided the required consent.

In addition, the following table illustrates varying ownership levels in New Rigetti Common Stock immediately following the consummation of the Business Combination (assuming Closing occurred on October 31, 2021 and an Exchange Ratio as of October 31, 2021 of 0.8182) based on the varying levels of redemptions by the public shareholders on a fully diluted basis, assuming full exercise of (i) public warrants or private placement warrants to purchase New Rigetti Common Stock and (ii) options and warrants to purchase shares of New Rigetti Common Stock that will be held by equityholders of Rigetti, and vesting of all restricted stock units.


Additional Dilution Sources (1)	Assuming No Redemption		% of Total (2)			Assuming 50% Redemption (3)		% of Total (2)			Assuming Maximum Redemption (4)		% of Total (2)			Assuming 100% Redemption (5)		% of Total (2)
Shares underlying Former Rigetti options ( 6)		12,261,219		8.47	%		12,261,219		9.42	%		12,261,219		10.61	%		12,261,219		11.13	%
Shares underlying Former Rigetti warrants (7)		8,960,551		6.34	%		8,960,551		7.06	%		8,960,551		7.98	%		8,960,551		8.38	%
Shares underlying Former Rigetti RSUs (8)		5,511,897		4.00	%		5,511,897		4.47	%		5,511,897		5.06	%		5,511,897		5.33	%
Supernova Warrants (9)		13,075,000		8.99	%		13,075,000		9.98	%		13,075,000		11.23	%		13,075,000		11.78	%
Total Additional Dilutive Sources		39,808,667		23.11	%		39,808,667		25.24	%		39,808,667		27.81	%		39,808,667		28.90	%

(1)

All share numbers and percentages for the Additional Dilution Sources are presented without the potential reduction of any amounts paid by the holders of the given Additional Dilution Sources and therefore may overstate the presentation of dilution. The Additional Dilution Sources exclude shares held by the Sponsor which are subject to vesting conditions, including the Sponsor Earn Out Shares, as defined below.

(2)

The Percentage of Total with respect to each Additional Dilution Source set forth below, including the Total Additional Dilutive Sources, includes the full amount of shares issued with respect to the applicable Additional Dilution Source in both the numerator and denominator. For example, in the illustrative redemption scenario, the Percentage of Total with respect to the Shares underlying Former Rigetti options would be calculated as follows: (a) 12,261,219 shares issued pursuant to the former Rigetti options; divided

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by (b) (i) 132,440,790 shares (the number of shares outstanding prior to any issuance pursuant to the shares underlying former Rigetti options) plus (ii) 12,261,219 shares issued pursuant to the shares underlying former Rigetti options.

(3)

Amount shown represents share redemption levels reflecting 50% of the Max Permitted Redemption scenario (approximately 42.15% redemptions).

(4)

Assumes that approximately 84.3% of Supernova’s outstanding public shares are redeemed in connection with the Business Combination, which is the maximum permitted amount of redemptions while still satisfying the conditions to the consummation of the Business Combination in the Merger Agreement.

(5)

(6)

Assumes exercise of all Rigetti options for 12,261,219 shares of New Rigetti, based on the outstanding options of Rigetti as of October 31, 2021 and assuming the Business Combination closes in the first quarter of 2022.

(7)

Assumes exercise of all Rigetti warrants to purchase 8,960,551 shares of New Rigetti Common Stock.

(8)

Assumes exercise of all restricted stock units for 5,511,897 shares of New Rigetti Common Stock.

(9)

Assumes exercise of all Supernova warrants for 13,075,000 shares of New Rigetti Common Stock.

Each of the above tables does not reflect additional dilution that may arise from exercise of the warrant issued to Ampere. The warrant provides for the purchase of an aggregate of 1,000,000 shares of New Rigetti Common Stock at an exercise price of $0.0001, since the exercise of such warrants is subject to certain conditions and cannot be exercised prior to June 30, 2022, at the earliest. See the section entitled “

Business Combination Proposal—Related Agreements—Subscription Agreements

” for additional information.

For further details, see “Business Combination Proposal—Consideration to Rigetti Equityholders in the Business Combination.”

Q: Why is Supernova proposing the Domestication?

The Supernova Board believes that there are significant advantages to us that will arise as a result of a change of our domicile to Delaware. Further, the Supernova Board believes that any direct benefit that the Delaware General Corporation Law (the “DGCL”) provides to a corporation also indirectly benefits its stockholders, who are the owners of the corporation. The Supernova Board believes that there are several reasons why transfer by way of continuation to Delaware is in the best interests of Supernova and its shareholders, including, (i) the prominence, predictability and flexibility of the DGCL, (ii) Delaware’s well-established principles of corporate governance and (iii) the increased ability for Delaware corporations to attract and retain qualified directors, each of the foregoing are discussed in greater detail in the section entitled “

Domestication Proposal—Reasons for the Domestication

.”

To effect the Domestication, we will file an application for deregistration with the Cayman Islands Registrar of Companies, together with the necessary accompanying documents, and file a certificate of corporate domestication and a certificate of incorporation with the Secretary of State of the State of Delaware, under which we will be domesticated and continue as a Delaware corporation.

The approval of the Domestication Proposal is a condition to closing the Business Combination under the Merger Agreement. The approval of the Domestication Proposal requires a special resolution under Cayman Islands law, being the affirmative vote of the holders of at least

two-thirds

(2/3) of the ordinary shares who, being present in person or by proxy and entitled to vote at the extraordinary general meeting, vote at the extraordinary general meeting. Because the Domestication Proposal involves a vote to continue Supernova outside the jurisdiction of the Cayman Islands, holders of Class B ordinary shares will have ten votes per Class B ordinary share and holders of Class A ordinary shares will have one vote per Class A ordinary share for purposes of the Domestication Proposal. Holders of Class B ordinary shares and Class A ordinary shares shall have one vote per share on all other proposals. Abstentions and broker

non-votes,

while considered present for the purposes of establishing a quorum, will not count as votes cast at the extraordinary general meeting, and otherwise will have no effect on a particular proposal.

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Q: What amendments will be made to the current constitutional documents of Supernova?

The consummation of the Business Combination is conditional, among other things, on the Domestication. Accordingly, in addition to voting on the Business Combination, Supernova’s shareholders also are being asked to consider and vote upon a proposal to approve the Domestication, and replace Supernova’s Existing Governing Documents, in each case, under Cayman Islands law with the Proposed Governing Documents, in each case, under the DGCL, which differ from the Existing Governing Documents in the following material respects:


	Existing Governing Documents	Proposed Governing Documents

Authorized Shares (Advisory Governing Documents Proposal A)	The share capital under the Existing Governing Documents is $55,500 divided into 500,000,000 Class A ordinary shares of par value $0.0001 per share, 50,000,000 Class B ordinary shares of par value $0.0001 per share and 5,000,000 preference shares of par value $0.0001 per share. See paragraph 5 of the Memorandum of Association.	The Proposed Governing Documents authorize 1,000,000,000 shares of New Rigetti Common Stock and 10,000,000 shares of New Rigetti Preferred Stock. See Article IV of the Proposed Certificate of Incorporation.

Authorize the Board of Directors to Issue Preferred Stock Without Stockholder Consent (Advisory Governing Documents Proposal B)	The Existing Governing Documents authorize the issuance of 5,000,000 preference shares with par value $0.0001 per share and with such designation, rights and preferences as may be determined from time to time by our Board. Accordingly, our board of directors is empowered under the Existing Governing Documents, without shareholder approval, to issue preference shares with dividend, liquidation, redemption, voting or other rights which could adversely affect the voting power or other rights of the holders of ordinary shares. See paragraph 3 of the Memorandum of Association and Article 3 of the Articles of Association.	The Proposed Governing Documents authorize the board of directors to issue all or any shares of preferred stock in one or more series and to fix for each such series such voting powers, full or limited, and such designations, preferences and relative, participating, optional or other special rights and such qualifications, limitations or restrictions thereof, as the board of directors may determine. See Article IV subsection B of the Proposed Certificate of Incorporation.

Shareholder/Stockholder Written Consent In Lieu of a Meeting ( Advisory Governing Documents Proposal C )	The Existing Governing Documents provide that resolutions may be passed by a vote in person, by proxy at a general meeting, or by unanimous written resolution.	The Proposed Governing Documents allow stockholders to vote in person or by proxy at a meeting of stockholders, but prohibit the ability of stockholders to act by written consent in lieu of a meeting.

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	Existing Governing Documents	Proposed Governing Documents
	See Article 22 of our Articles of Association.	See Article IX subsection 2 of the Proposed Certificate of Incorporation.

Corporate Name ( Advisory Governing Documents Proposal D )	The Existing Governing Documents provide the name of the company is “Supernova Partners Acquisition Company II, Ltd.” See paragraph 1 of our Memorandum of Association.	The Proposed Governing Documents will provide that the name of the corporation will be “Rigetti Computing, Inc.” See Article I of the Proposed Certificate of Incorporation.

Perpetual Existence (Advisory Governing Documents Proposal D)	The Existing Governing Documents provide that if we do not consummate a business combination (as defined in the Existing Governing Documents) by March 4, 2023 (twenty-four months after the closing of Supernova’s initial public offering), Supernova will cease all operations except for the purposes of winding up and will redeem the shares issued in Supernova’s initial public offering and liquidate its trust account. See Article 49 of our Articles of Association.	The Proposed Governing Documents do not include any provisions relating to New Rigetti’s ongoing existence; the default under the DGCL will make New Rigetti’s existence perpetual. This is the default rule under the DGCL.

Exclusive Forum ( Advisory Governing Documents Proposal D )	The Existing Governing Documents do not contain a provision adopting an exclusive forum for certain shareholder litigation.	The Proposed Governing Documents adopt Delaware as the exclusive forum for certain stockholder litigation and the United States federal district court as the exclusive forum for litigation arising out of the Securities Act. See Article VIII of the Proposed Certificate of Incorporation.

Provisions Related to Status as Blank Check Company ( Advisory Governing Documents Proposal D )	The Existing Governing Documents set forth various provisions related to our status as a blank check company prior to the consummation of a business combination. See Article 49 of our Articles of Association.	The Proposed Governing Documents do not include such provisions related to our status as a blank check company, which no longer will apply upon consummation of the Business Combination, as we will cease to be a blank check company at such time.

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Q: How will the Domestication affect my ordinary shares, warrants and units?

In connection with the Domestication, immediately prior to (but no later than the day preceding) the Closing Date: (i) each issued and outstanding Class A ordinary share and each issued and outstanding Class B ordinary share, of Supernova will be converted into one share of common stock, par value $0.0001 per share, of New Rigetti; (ii) each issued and outstanding whole warrant to purchase Class A ordinary shares of Supernova will automatically represent the right to purchase one share of New Rigetti Common Stock at an exercise price of $11.50 per share on the terms and conditions set forth in the Supernova warrant agreement; (iii) each issued and outstanding Supernova preference share will continue to exist as a share of preferred stock of New Rigetti; (iv) the governing documents of Supernova will be amended and restated and become the certificate of incorporation and the bylaws of New Rigetti as described in this proxy statement/prospectus; and (v) Supernova’s name will change to “Rigetti Computing, Inc.” In connection with clauses (i) and (ii) of this paragraph, each issued and outstanding unit of Supernova that has not been previously separated into the underlying Class A ordinary shares of Supernova and the underlying warrants of Supernova prior to the Domestication will be cancelled and will entitle the holder thereof to one share of New Rigetti Common Stock and

one-fourth

Domestication Proposal

.”

Q: What are the U.S. federal income tax consequences of the Domestication?

As discussed more fully under “

U.S. Federal Income Tax Considerations

,” it is intended that the Domestication qualify as a “reorganization” within the meaning of Section 368(a)(l)(F) of the U.S. Internal Revenue Code of 1986, as amended (the “Code”). Assuming that the Domestication so qualifies, and subject to the “passive foreign investment company” (“PFIC”) rules discussed below and under “

U.S. Federal Income Tax Considerations—I. U.S. Holders—A. Tax Effects of the Domestication to U.S. Holders—5. PFIC Considerations

,” U.S. Holders (as defined in “

U.S. Federal Income Tax Considerations—I. U.S. Holders

”) will be subject to Section 367(b) of the Code and, as a result:

•

A U.S. Holder whose Class A ordinary shares have a fair market value of less than $50,000 and who, on the date of the Domestication, owns (actually or constructively) less than 10% of the total combined voting power of all classes of Supernova stock entitled to vote and less than 10% of the total value of all classes of Supernova stock generally will not recognize any gain or loss and will not be required to include any part of Supernova’s earnings in income in connection with the Domestication;

•

A U.S. Holder whose Class A ordinary shares have a fair market value of $50,000 or more and who, on the date of the Domestication, owns (actually or constructively) less than 10% of the total combined voting power of all classes of Supernova stock entitled to vote and less than 10% of the total value of all classes of Supernova stock generally will recognize gain (but not loss) on the exchange of Class A ordinary shares for New Rigetti Common Stock pursuant to the Domestication. As an alternative to recognizing gain, such U.S. Holder may file an election to include in income as a deemed dividend deemed paid by Supernova the “all earnings and profits amount” (as defined in the Treasury Regulations under Section 367 of the Code) attributable to its Class A ordinary shares provided certain other requirements are satisfied; and

•

A U.S. Holder who, on the date of the Domestication, owns (actually or constructively) 10% or more of the total combined voting power of all classes of Supernova stock entitled to vote or 10% or more of the total value of all classes of Supernova stock generally will be required to include in income as a deemed dividend deemed paid by Supernova the “all earnings and profits amount” attributable to its Class A ordinary shares as a result of the Domestication.

Supernova does not expect to have significant cumulative earnings and profits, if any, on the date of the Domestication.

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As discussed more fully under “

U.S. Federal Income Tax Considerations—I. U.S. Holders—A. Tax Effects of the Domestication to U.S. Holders—5. PFIC Considerations

,” Supernova believes that it is likely classified as a PFIC for U.S. federal income tax purposes. In such case, notwithstanding the U.S. federal income tax consequences of the Domestication discussed in the foregoing, proposed Treasury Regulations under Section 1291(f) of the Code (which have a retroactive effective date), if finalized in their current form, generally would require a U.S. Holder to recognize gain on the exchange of Class A ordinary shares or warrants for New Rigetti Common Stock or warrants pursuant to the Domestication. Any such gain would be taxable income with no corresponding receipt of cash in the Domestication. The tax on any such gain would be imposed at the rate applicable to ordinary income and an interest charge would apply based on a complex set of rules. In addition, the proposed Treasury Regulations provide coordinating rules with other sections of the Code, including Section 367(b), which affect the manner in which the rules under such other sections apply to transfers of PFIC stock. However, it is difficult to predict whether, in what form, and with what effective date, final Treasury Regulations under Section 1291(f) of the Code may be adopted and how any such Treasury Regulations would apply. Importantly, however, U.S. Holders that make or have made certain elections discussed further under “

U.S. Federal Income Tax Considerations—I. U.S. Holders—A. Tax Effects of the Domestication to U.S. Holders—5. PFIC Considerations—d. QEF Election and

Mark-to-Market

Election

” with respect to their Class A ordinary shares are generally not subject to the same gain recognition rules under the currently proposed Treasury Regulations under Section 1291(f) of the Code. Currently, there are no elections available that apply to warrants, and the application of the PFIC rules to the warrants is unclear. For a more complete discussion of the potential application of the PFIC rules to U.S. Holders as a result of the Domestication, see “

U.S. Federal Income Tax Considerations—I. U.S. Holders

.”

Each U.S. Holder of Class A ordinary shares or warrants is urged to consult its own tax advisor concerning the application of the PFIC rules, including the proposed Treasury Regulations, to the exchange of Class A ordinary shares and warrants for New Rigetti Common Stock and warrants pursuant to the Domestication.

Additionally, the Domestication may cause

Non-U.S.

Holders (as defined in “

U.S. Federal Income Tax Considerations—II.

Non-U.S.

Holders

”) to become subject to U.S. federal income withholding taxes on any amounts treated as dividends paid in respect of such

Non-U.S.

Holder’s New Rigetti Common Stock after the Domestication.

The tax consequences of the Domestication are complex and will depend on a holder’s particular circumstances. All holders are urged to consult their tax advisor regarding the tax consequences to them of the Domestication, including the applicability and effect of U.S. federal, state, local and

non-U.S.

tax laws. For a more complete discussion of the U.S. federal income tax considerations of the Domestication, see “

U.S. Federal Income Tax Considerations

.”

Q: Do I have redemption rights?

If you are a holder of public shares, you have the right to request that we redeem all or a portion of your public shares for cash provided that you follow the procedures and deadlines described elsewhere in this proxy statement/prospectus. Public shareholders may elect to redeem all or a portion of the public shares held by them regardless of if or how they vote in respect of the Business Combination Proposal. If you wish to exercise your redemption rights, please see the answer to the next question: “

How do I exercise my redemption rights?

”

Notwithstanding the foregoing, a public shareholder, together with any affiliate of such public shareholder or any other person with whom such public shareholder is acting in concert or as a “group” (as defined in Section 13(d)(3) of the Exchange Act), will be restricted from redeeming its public shares with respect to more than an aggregate of 15% of the public shares. Accordingly, if a public shareholder, alone or acting in concert or as a group, seeks to redeem more than 15% of the public shares, then any such shares in excess of that 15% limit would not be redeemed for cash.

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The Initial Shareholders have agreed to waive their redemption rights with respect to all of their ordinary shares in connection with the consummation of the Business Combination. Such shares will be excluded from the pro rata calculation used to determine the

per-share

redemption price.

Q: How do I exercise my redemption rights?

In connection with the proposed Business Combination, pursuant to the Existing Governing Documents, Supernova’s public shareholders may request that Supernova redeem all or a portion of such public shares for cash if the Business Combination is consummated. If you are a public shareholder and wish to exercise your right to redeem the public shares, you must: (a) hold public shares, or (b) if you hold public shares through units, elect to separate your units into the underlying public shares and public warrants prior to exercising your redemption rights with respect to the public shares;

•

submit a written request to AST, Supernova’s transfer agent, in which you (a) request that we redeem all or a portion of your public shares for cash, and (b) identify yourself as the beneficial holder of the public shares and provide your legal name, phone number and address; and

•

deliver your share certificates (if any) and other redemption forms (as applicable) to AST, our transfer agent, physically or electronically through The Depository Trust Company (“DTC”).

The address of AST, Supernova’s transfer agent, is listed under the question “

Who can help answer my questions?

” below.

Holders of units must elect to separate the units into the underlying public shares and public warrants prior to exercising redemption rights with respect to the public shares. If holders hold their units in an account at a brokerage firm or bank, holders must notify their broker or bank that they elect to separate the units into the underlying public shares and public warrants, or if a holder holds units registered in its own name, the holder must contact AST, our transfer agent, directly and instruct them to do so.

Public shareholders will be entitled to request that their public shares be redeemed for a pro rata portion of the amount then on deposit in the trust account as of two business days prior to the consummation of the Business Combination including interest earned on the funds held in the trust account and not previously released to us (net of taxes payable). For illustrative purposes, as of September 30, 2021, this would have amounted to approximately $10.00 per issued and outstanding public share. However, the proceeds deposited in the trust account could become subject to the claims of our creditors, if any, which could have priority over the claims of our public shareholders, regardless of whether such public shareholders vote or, if they do vote, irrespective of if they vote for or against the Business Combination Proposal. Therefore, the per share distribution from the trust account in such a situation may be less than originally expected due to such claims. Whether you vote, and if you do vote irrespective of how you vote, on any proposal, including the Business Combination Proposal, will have no impact on the amount you will receive upon exercise of your redemption rights. It is expected that the funds to be distributed to public shareholders electing to redeem their public shares will be distributed promptly after the consummation of the Business Combination.

Any request for redemption, once made by a holder of public ordinary shares, may not be withdrawn once submitted to Supernova unless the Supernova Board determine (in their sole discretion) to permit the withdrawal of such redemption request (which they may do in whole or in part). If you deliver your share certificates (if any) and other redemption forms (as applicable) for redemption to AST, our transfer agent, and later decide prior to the extraordinary general meeting not to elect redemption, you may request that our transfer agent return the

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share certificates (if any) and the shares (physically or electronically) to you. You may make such request by contacting AST, our transfer agent, at the phone number or address listed at the end of this section.

Any corrected or changed written exercise of redemption rights must be received by AST, our transfer agent, prior to the vote taken on the Business Combination Proposal at the extraordinary general meeting.

No request

for redemption will be honored unless the holder’s share certificates (if any) and other redemption forms have been delivered (either physically or electronically) to AST, our transfer agent, at least two business days prior to the vote at the extraordinary general meeting.

If a holder of public shares properly makes a request for redemption and delivers the public share certificates (if any) along with the redemption forms (as applicable) as described above, then, if the Business Combination is consummated, we will redeem the public shares for a pro rata portion of funds deposited in the trust account, calculated as of two business days prior to the consummation of the Business Combination. The redemption takes place following the Domestication and, accordingly, it is shares of New Rigetti Common Stock that will be redeemed immediately after consummation of the Business Combination.

If you are a holder of public shares and you exercise your redemption rights, such exercise will not result in the loss of any warrants that you may hold.

Q: If I am a holder of units, can I exercise redemption rights with respect to my units?

No. Holders of issued and outstanding units must elect to separate the units into the underlying public shares and public warrants prior to exercising redemption rights with respect to the public shares. If you hold your units in an account at a brokerage firm or bank, you must notify your broker or bank that you elect to separate the units into the underlying public shares and public warrants, or if you hold units registered in your own name, you must contact AST, our transfer agent, directly and instruct them to do so. The redemption rights include the requirement that a holder must identify itself in writing as a beneficial holder and provide its legal name, phone number and address to AST in order to validly redeem its shares. You are requested to cause your public shares to be separated and your share certificates (if any) and other redemption forms (as applicable) delivered to AST, our transfer agent, by 5:00 p.m., Eastern Time, on , 2022 (two business days before the extraordinary general meeting) in order to exercise your redemption rights with respect to your public shares.

Q: What are the U.S. federal income tax consequences of exercising my redemption rights?

The U.S. federal income tax consequences of exercising your redemption rights with respect to your Class A ordinary shares to receive cash from the trust account in exchange for New Rigetti Common Stock depend on your particular facts and circumstances. It is possible that you may be treated as selling such New Rigetti Common Stock and, as a result, recognize capital gain or capital loss. It is also possible that the redemption may be treated as a distribution for U.S. federal income tax purposes depending on the amount of New Rigetti Common Stock that you own or are deemed to own (including through the ownership of New Rigetti warrants). For a more complete discussion of the U.S. federal income tax considerations of an exercise of redemption rights, see “

U.S. Federal Income Tax Considerations

.”

Additionally, because the Domestication will occur prior to the redemption of any shareholder, U.S. Holders (as defined in “

U.S. Federal Income Tax Considerations—I. U.S. Holders

”) exercising redemption rights will be subject to the potential tax consequences of Section 367 of the Code as well as potential tax consequences of the U.S. federal income tax rules relating to PFICs. The tax consequences of Section 367 of the Code and the PFIC rules are discussed more fully below under “

U.S. Federal Income Tax Considerations—I. U.S. Holders

.”

All holders considering exercising redemption rights are urged to consult their tax advisor on the tax consequences to them of an exercise of redemption rights, including the applicability and effect of U.S. federal, state, local and

non-U.S.

tax laws.

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Q: What happens to the funds deposited in the trust account after consummation of the Business Combination?

Following the closing of our initial public offering, an amount equal to $345,000,000 ($10.00 per unit) of the net proceeds from our initial public offering and the sale of the private placement warrants. As of September 30, 2021, funds in the trust account totaled approximately $345 million and were invested in U.S. government treasury bills with a maturity of 185 days or less or in money market funds investing solely in U.S. Treasuries and meeting certain conditions under

Rule 2a-7 under

the Investment Company Act of 1940, as amended. These funds will remain in the trust account, except for the withdrawal of interest to pay taxes, if any, until the earliest of (i) the completion of Supernova’s initial business combination, (ii) the redemption of any public shares properly tendered in connection with a shareholder vote to amend the Existing Governing Documents to modify the substance and timing of our obligation to redeem 100% of the public shares if Supernova does not complete a business combination by March 4, 2023, or (iii) the redemption of all of the public shares if Supernova is unable to complete a business combination by March 4, 2023 (unless such date is extended in accordance with the Existing Governing Documents), subject to applicable law.

Upon consummation of the Business Combination, the funds deposited in the trust account will be released to pay holders of public shares who properly exercise their redemption rights; to pay transaction fees and expenses associated with the Business Combination; and for working capital and general corporate purposes of New Rigetti following the Business Combination. See “

Summary of the Proxy Statement/Prospectus—Sources and Uses of Funds for the Business Combination

.”

Q: What happens if a substantial number of the public shareholders vote in favor of the Business Combination Proposal and exercise their redemption rights?

Our public shareholders are not required to vote “FOR” the Business Combination in order to exercise their redemption rights. Accordingly, the Business Combination may be consummated even though the funds available from the trust account and the number of public shareholders are reduced as a result of redemptions by public shareholders. However, a condition to the consummation of the Business Combination is that the aggregate cash proceeds available for release from the trust account (including funds from the PIPE Financing) in connection with the transactions contemplated in the Merger Agreement is equal to or greater than $165 million, after deducting Supernova’s unpaid expenses.

In no event will Supernova redeem public shares in an amount that would cause our net tangible assets (as determined in accordance with Rule

3a51-1(g)(1)

of the Exchange Act) to be less than $5,000,001 after giving effect to the transactions contemplated by the Merger Agreement and the PIPE Financing.

Additionally, as a result of redemptions, the trading market for the New Rigetti Common Stock may be less liquid than the market for the public shares was prior to consummation of the Business Combination and we may not be able to meet the listing standards for Nasdaq or another national securities exchange.

Q: What conditions must be satisfied to complete the Business Combination?

The consummation of the Business Combination is conditioned upon, among other things, (i) approval by Supernova’s and Rigetti’s respective stockholders, (ii) the expiration or termination of the waiting period under the HSR Act and the obtaining of any consents required under antitrust laws or foreign direct investment laws in the jurisdictions specified on a schedule, (iii) no law or order enjoining or prohibiting the consummation of the Transactions being in force, (iv) Supernova having at least $5,000,001 of net tangible assets as of the Closing, (v) receipt of approval for listing on the New York Stock Exchange of the shares of New Rigetti Common Stock to be issued in connection with the Transactions, (vi) completion of the Domestication, (vii) the effectiveness of this registration statement

on Form S-4, (viii)

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Closing and (x) solely as relates to Rigetti’s obligation to consummate the Transaction, Supernova having at least $165,000,000 of available cash at the Closing. Therefore, unless these conditions are waived by the applicable parties to the Merger Agreement, the Merger Agreement could terminate and the Business Combination may not be consummated.

For more information about conditions to the consummation of the Business Combination, see “

Business Combination Proposal—Conditions to Closing of the Business Combination

.”

Q: When do you expect the Business Combination to be completed?

It is currently expected that the Business Combination will be consummated in the first quarter of 2022. This date depends, among other things, on the approval of the proposals to be put to Supernova shareholders at the extraordinary general meeting. However, such extraordinary general meeting could be adjourned if the Adjournment Proposal is adopted by our shareholders at the extraordinary general meeting and we elect to adjourn the extraordinary general meeting to a later date or dates, if necessary (i) to solicit additional proxies for the purpose of obtaining approval by the shareholders of Supernova for each of the proposals necessary to consummate the transactions contemplated by the Merger Agreement, (ii) for the absence of a quorum or (iii) if the holders of the Class A ordinary shares have elected to redeem a number of Class A ordinary shares as of such time that would reasonably be expected to result in the conditions required for the Closing of the Merger Agreement not to be satisfied; provided that, without the consent of Rigetti, in no event shall the extraordinary general meeting of shareholders be adjourned to a date that is more than fifteen (15) business days later than the most recently adjourned meeting or to a date that is five (5) business days prior to the termination date of the Merger Agreement. For a description of the conditions for the completion of the Business Combination, see “

Business Combination Proposal—Conditions to Closing of the Business Combination

.”

Q: What happens if the Business Combination is not consummated?

Supernova will not complete the Domestication to Delaware unless all other conditions to the consummation of the Business Combination have been satisfied or waived by the parties in accordance with the terms of the Merger Agreement. If Supernova is not able to consummate the Business Combination with Rigetti nor able to complete another business combination by March 4, 2023, we will (i) cease all operations except for the purpose of winding up, (ii) as promptly as reasonably possible but not more than ten business days thereafter, redeem the public shares, at a

per-share

price, payable in cash, equal to the aggregate amount then on deposit in the trust account, including interest (which interest shall be net of taxes payable, and less up to $100,000 of interest to pay dissolution expenses), divided by the number of then outstanding public shares, which redemption will completely extinguish public shareholders’ rights as shareholders (including the right to receive further liquidating distributions, if any), subject to applicable law, and (iii) as promptly as reasonably possible following such redemption, subject to the approval of our remaining shareholders and the Supernova Board, liquidate and dissolve, subject in each case to our obligations under Cayman Islands law to provide for claims of creditors and the requirements of other applicable laws.

Q: Do I have appraisal rights in connection with the proposed Business Combination and the proposed Domestication?

Neither our shareholders nor our warrant holders have appraisal rights in connection with the Business Combination or the Domestication under Cayman Islands law or under the DGCL.

Q: What do I need to do now?

You should read this proxy statement/prospectus, including the Annexes and the documents referred to herein, carefully and in their entirety and to consider how the Business Combination will affect you as a shareholder and/or warrant holder. Our shareholders should then vote as soon as possible in accordance with the instructions provided in this proxy statement/prospectus and on the enclosed proxy card.

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Q: How do I vote?

If you are a holder of record of ordinary shares on the record date for the extraordinary general meeting, you may vote in person virtually at the extraordinary general meeting, or by submitting a proxy for the extraordinary general meeting. You may submit your proxy by completing, signing, dating and returning the enclosed proxy cards, as applicable, in the

accompanying pre-addressed postage-paid

envelope.

If you hold your shares in

“street name,” which means your shares are held of record by a broker, bank or nominee, you should contact your broker, bank or nominee to ensure that votes

related to the shares you beneficially own are properly counted. In this regard, you must provide the broker, bank or nominee with instructions on how to vote your shares or, if you wish to virtually attend the extraordinary general meeting and vote in person, obtain a valid proxy from your broker, bank or nominee.

Q: If my shares are held in “street name,” will my broker, bank or nominee automatically vote my shares for me?

No. If your shares are held in a stock brokerage account or by a bank or other nominee, you are considered the “beneficial holder” of the shares held for you in what is known as “street name.” If this is the case, this proxy statement/prospectus may have been forwarded to you by your brokerage firm, bank or other nominee, or its agent. As the beneficial holder, you have the right to direct your broker, bank or other nominee as to how to vote your shares. If you do not provide voting instructions to your broker on a particular proposal on which your broker does not have discretionary authority to vote, your shares will not be voted on that proposal. This is called a “broker

non-vote.”

Abstentions and broker

non-votes,

while considered present for the purposes of establishing a quorum, will not count as votes cast at the extraordinary general meeting, and otherwise will have no effect on a particular proposal. If you decide to vote, you should provide instructions to your broker, bank or other nominee on how to vote in accordance with the information and procedures provided to you by your broker, bank or other nominee.

Q: When and where will the extraordinary general meeting be held?

The extraordinary general meeting will be held at , Eastern Time, on , 2022, at the offices of located at , and virtually live via webcast at , or such other date, time and place to which such meeting may be adjourned or postponed, to consider and vote upon the proposals.

Q: How will the

COVID-19

pandemic impact

in-person

voting at the General Meeting?

We intend to hold the extraordinary general meeting in person. However, we are sensitive to the public health and travel concerns our shareholders may have and recommendations that public health officials may issue in light of the evolving coronavirus

(“COVID-19”)

situation. As a result, we may impose additional procedures or limitations on meeting attendees. We plan to announce any such updates in a press release filed with the SEC and on our proxy website at , and we encourage you to check this website prior to the meeting if you plan to attend.

How do I attend a virtual meeting?

A: As a registered shareholder, you will receive the proxy card from AST. The form contains instructions on how to attend the virtual meeting including the URL address, along with your control number. You will need your control number for access. If you do not have your control number, contact AST at the phone number or

e-mail

address below. AST support contact information is as follows: (718)

921-8200,

or email help@astfinancial.com.

You can

pre-register

to attend the virtual meeting starting at , Eastern Time, on , 2022. Enter the URL address into your browser , enter your control number, name and email address. Once you

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pre-register

you can vote or enter questions in the chat box. At the start of the meeting you will need to

re-log

in using your control number and will also be prompted to enter your control number if you vote during the meeting.

Beneficial investors, who own their investments through a bank or broker, will need to contact AST to receive a control number. If you plan to vote at the meeting you will need to have a legal proxy from your bank or broker or if you would like to join and not vote AST will issue you a guest control number with proof of ownership. Either way you must contact AST specific instructions on how to receive the control number. We can be contacted at the number or email address above. Please allow up to 72 hours prior to the meeting for processing your control number.

If you do not have internet capabilities, you can listen only to the meeting by dialing (800)

776-9437

(toll-free) within the United States and Canada or (718)

921-8500

(standard rates apply) outside of the United States and Canada and, when prompted, entering the pin number. This

is listen-in only;

you will not be able to vote or enter questions during the meeting.

Q: What impact will the

COVID-19

Pandemic have on the Business Combination?

Given the ongoing and dynamic nature of the circumstances, it is difficult to predict the impact of the coronavirus outbreak on the business of Supernova and Rigetti, and there is no guarantee that efforts by Supernova and Rigetti to address the adverse impacts of the coronavirus will be effective. The extent of such impact will depend on future developments, which are highly uncertain and cannot be predicted, including new information which may emerge concerning the severity of the coronavirus and actions taken to contain the coronavirus or its impact, among others. If Supernova or Rigetti are unable to recover from a business disruption on a timely basis, the Business Combination and New Rigetti’s business, financial condition and results of operations following the completion of the Business Combination would be adversely affected. The Business Combination may also be delayed and adversely affected by the coronavirus outbreak and become more costly. Each of Supernova and Rigetti may also incur additional costs to remedy damages caused by any such disruptions, which could adversely affect its financial condition and results of operations.

Q: Who is entitled to vote at the extraordinary general meeting?

We have fixed January 18, 2022 as the record date for the extraordinary general meeting. If you were a shareholder of Supernova at the close of business on the record date, you are entitled to vote on matters that come before the extraordinary general meeting. However, a shareholder may only vote his or her shares if he, she or they is present in person or is represented by proxy at the extraordinary general meeting.

Q: How many votes do I have?

With the exception of our Initial Shareholders, who are entitled to ten votes for each Class B ordinary share they hold for purposes of voting on the Domestication Proposal, Supernova shareholders are entitled to one vote at the extraordinary general meeting for each ordinary share held of record as of the record date. As of the close of business on the record date for the extraordinary general meeting, there were 34,500,000 Class A ordinary shares issued and outstanding and 8,625,000 Class B ordinary shares issued and outstanding, all of which are held by the Initial Shareholders.

Q: What constitutes a quorum?

A quorum of Supernova shareholders is necessary to hold a valid meeting. A quorum will be present at the extraordinary general meeting if one or more shareholders who together hold not less than a majority of the issued and outstanding ordinary shares entitled to vote at the extraordinary general meeting are represented in person or by proxy at the extraordinary general meeting. As of the record date for the extraordinary general meeting, 21,562,501 ordinary shares would be required to achieve a quorum for each proposal contained in this proxy statement.

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Q: What vote is required to approve each proposal at the extraordinary general meeting?

The following votes are required for each proposal at the extraordinary general meeting:

•

Business Combination Proposal:

The approval of the Business Combination Proposal requires an ordinary resolution under Cayman Islands law, being the affirmative vote of a majority of the ordinary shares represented in person or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting, vote at the extraordinary general meeting.

•

Domestication Proposal:

The approval of the Domestication Proposal requires a special resolution under Cayman Islands law, being the affirmative vote of the holders of at least

two-thirds (2/3)

of the ordinary shares who, being present in person or by proxy and entitled to vote at the extraordinary general meeting, vote at the extraordinary general meeting. Holders of our Class B ordinary shares will be entitled to ten votes for each Class B ordinary share for purposes of the Domestication Proposal.

•

Proposed Charter and Bylaws Proposal:

The approval of the Proposed Charter and Bylaws Proposal requires a special resolution under Cayman Islands law, being the affirmative vote of the holders of at least

two-thirds

(2/3) of the ordinary shares who, being present in person or by proxy and entitled to vote at the extraordinary general meeting vote at the extraordinary general meeting.

•

Advisory Governing Documents Proposals:

The separate approval of each of the Advisory Governing Documents Proposals requires an ordinary resolution under Cayman Islands law, being the affirmative vote of a majority of the ordinary shares represented in person or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting.

•

Stock Issuance Proposal:

The approval of the Stock Issuance Proposal requires an ordinary resolution under Cayman Islands law, being affirmative vote of a majority of the ordinary shares represented in person or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting, vote at the extraordinary general meeting.

•

Director Election Proposal:

The approval of the Director Election Proposal requires an ordinary resolution under Cayman Islands law, being the affirmative vote of a majority of the ordinary shares represented in person or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting.

•

Equity Incentive Plan Proposal:

The approval of the Equity Incentive Plan Proposal requires an ordinary resolution under Cayman Islands law, being the affirmative vote of a majority of the ordinary shares represented in person or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting, vote at the extraordinary general meeting.

•

Employee Stock Purchase Plan Proposal:

The approval of the Employee Stock Purchase Plan Proposal requires an ordinary resolution under Cayman Islands law, being the affirmative vote of a majority of the ordinary shares who, being present in person or by proxy and entitled to vote at the extraordinary general meeting, vote at the extraordinary general meeting.

•

Adjournment Proposal:

The approval of the Adjournment Proposal requires an ordinary resolution under Cayman Islands law, being the affirmative vote of a majority of the ordinary shares represented in person or by proxy and entitled to vote thereon and who vote at the extraordinary general meeting, vote at the extraordinary general meeting.

As of the record date, Supernova had 43,125,000 ordinary shares issued and outstanding, of which 34,500,000 were Class A ordinary shares and 8,625,000 were Class B ordinary shares. Supernova shareholders are entitled to one vote at the extraordinary general meeting for each ordinary share held of record as of the record date. The holders of our Class B ordinary shares will be entitled to ten votes for each Class B ordinary share when voting on the Domestication Proposal.

Assuming all holders that are entitled to vote on such matter vote all of their ordinary shares in person or by proxy, 21,562,501 shares will need to be voted in favor of each of the Business Combination Proposal, each of

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the Advisory Governing Documents Proposals, the Stock Issuance Proposal, the Director Election Proposal, the Equity Incentive Plan Proposal, the Employee Stock Purchase Plan Proposal, and the Adjournment Proposal in order to approve each of the Business Combination Proposal, each of the Advisory Governing Documents Proposals, the Stock Issuance Proposal, the Director Election Proposal, the Equity Incentive Plan Proposal, the Employee Stock Purchase Plan Proposal, and the Adjournment Proposal.

Of these 21,562,501 shares, 8,625,000 Class B ordinary shares are held by the Initial Shareholders, and each of the Initial Shareholders have agreed to vote all of their ordinary shares in favor of each of the Business Combination Proposal, each of the Advisory Governing Documents Proposals, the Stock Issuance Proposal, the Director Election Proposal, the Equity Incentive Plan Proposal, the Employee Stock Purchase Plan Proposal, and the Adjournment Proposal. As a result, assuming all holders that are entitled to vote on such matters vote all of their ordinary shares in person or by proxy, 12,937,501 (or 37.5%) of the shares not held by the Initial Shareholders need to be voted in favor to approve each of the foregoing proposals.

Assuming all holders that are entitled to vote on such matter vote all of their ordinary shares in person or by proxy, 28,750,001 shares will need to be voted in favor of the Proposed Charter and Bylaws Proposal in order to approve the Proposed Charter and Bylaws Proposal. Of these 28,750,001 shares, 8,625,000 Class B ordinary shares are held by the Initial Shareholders, each of whom has agreed to vote all of their ordinary shares in favor of the Proposed Charter and Bylaws Proposal. As a result, assuming all holders that are entitled to vote on such matter vote all of their ordinary shares in person or by proxy, 20,125,000 (or 58.3%) of the shares not held by the Initial Shareholders need to be voted in favor to approve the foregoing proposal.

Assuming all holders of the Class B ordinary shares that are entitled to vote on the Domestication Proposal vote all of their Class B ordinary shares in person or by proxy, then no other holders of ordinary shares will be needed to approve the Domestication Proposal if a quorum is present at the extraordinary general meeting. All holders of the Class B ordinary shares have agreed to vote all of their ordinary shares in favor of the Domestication Proposal.

Q: What are the recommendations of the Supernova Board?

The Supernova Board believes that the Business Combination Proposal and the other proposals to be presented at the extraordinary general meeting are in the best interest of Supernova and its shareholders and unanimously recommends that its shareholders vote “FOR” the Business Combination Proposal, “FOR” the Domestication Proposal, “FOR” the Proposed Charter and Bylaws Proposal, “FOR” each of the separate Advisory Governing Documents Proposals, “FOR” the Stock Issuance Proposal, “FOR” the Director Election Proposal, “FOR” the Equity Incentive Plan Proposal, “FOR” the Employee Stock Purchase Plan Proposal, and “FOR” the Adjournment Proposal, in each case, if presented to the extraordinary general meeting.

Business Combination Proposal—Interests of Supernova’s Sponsor, Directors and Executive Officers in the Business Combination

” for a further discussion of these considerations.

Q: How do Sponsor and the other Initial Shareholders intend to vote their shares?

Unlike some other blank check companies in which the Initial Shareholders agree to vote their shares in accordance with the majority of the votes cast by the public shareholders in connection with an initial business combination, our Initial Shareholders have agreed to vote all of their shares in favor of all the proposals being presented at the extraordinary general meeting. As of the date of this proxy statement/prospectus, our Initial Shareholders own approximately 20% of the issued and outstanding ordinary shares.

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At any time at or prior to the Business Combination, our Initial Shareholders, Rigetti and/or their directors, officers, advisors or respective affiliates may enter into transactions with investors and others to provide them with incentives to acquire public shares or vote their public shares in favor of the Condition Precedent Proposals. The above-described activity could be especially prevalent in and around the time of Closing. The purpose of such transactions would be to increase the likelihood of satisfaction of the requirements that (i) the Business Combination Proposal, each of the Advisory Governing Documents Proposals, the Stock Issuance Proposal, the Director Election Proposal, the Equity Incentive Plan Proposal, the Employee Stock Purchase Plan Proposal and the Adjournment Proposal are approved by the affirmative vote of at least a majority of the votes cast by the holders of the issued ordinary shares present in person or represented by proxy at the extraordinary general meeting and entitled to vote on such matter, (ii) the Domestication Proposal, the Proposed Charter and Bylaws Proposal are approved by the affirmative vote of at least

two-thirds

(2/3) of the votes cast by the holders of the issued ordinary shares present in person or represented by proxy at the extraordinary general meeting and entitled to vote on such matter, (iii) otherwise limit the number of public shares electing to redeem and (iv) New Rigetti’s net tangible assets (as determined in accordance with Rule

3a51-1(g)(1)

of the Exchange Act) being at least $5,000,001 after giving effect to the transactions contemplated by the Merger Agreement and the PIPE Financing.

Entering into any such arrangements may have a depressive effect on the ordinary shares. For example, as a result of these arrangements, an investor or holder may have the ability to effectively purchase shares at a price lower than market and may therefore be more likely to sell the shares he, she or they own, either at or prior to the Business Combination.

If such transactions are effected, the consequence could be to cause the Business Combination to be consummated in circumstances where such consummation could not otherwise occur. Entering into the transactions described above would allow our Initial Shareholders, Rigetti or their directors, officers, advisors or respective affiliates to exert more influence over the approval of the proposals to be presented at the extraordinary general meeting and would likely increase the chances that such proposals would be approved. We will file or submit a Current Report on Form

8-K

to disclose any material arrangements entered into by any of the aforementioned persons that would affect the vote on the proposals to be put to the extraordinary general meeting or the redemption threshold. Any such report will include descriptions of any arrangements entered into by any of the aforementioned persons.

Q: What happens if I sell my shares before the extraordinary general meeting?

The record date for the extraordinary general meeting is earlier than the date of the extraordinary general meeting and earlier than the date that the Business Combination is expected to be completed. If you transfer your public shares after the applicable record date, but before the extraordinary general meeting, you will retain your right to vote at such general meeting unless you grant a proxy to the transferee.

Q: May I change my vote after I have mailed my signed proxy card?

Yes. Shareholders may send a later-dated, signed proxy card to our secretary at our address (set forth below) so that it is received by our secretary prior to the vote at the extraordinary general meeting (which is scheduled to take place on , 2022) or attend the extraordinary general meeting in person and vote. Shareholders may also revoke their proxy by sending a notice of revocation to our secretary, which must be received by our secretary prior to the vote at the extraordinary general meeting. However, if your shares are held in “street name” by your broker, bank or another nominee, you must contact your broker, bank or other nominee to change your vote.

Q: What happens if I fail to take any action with respect to the extraordinary general meeting?

If you fail to vote with respect to the extraordinary general meeting and the Business Combination is approved by shareholders and the Business Combination is consummated, you will become a stockholder and/or

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warrant holder of New Rigetti. If you fail to vote with respect to the extraordinary general meeting and the Business Combination is not approved, you will remain a shareholder and/or warrant holder of Supernova. However, if you fail to vote with respect to the extraordinary general meeting, you will nonetheless be able to elect to redeem your public shares in connection with the Business Combination.

Q: What should I do with my share certificates, warrant certificates or unit certificates?

Our shareholders who exercise their redemption rights must deliver (either physically or electronically) their share certificates to AST, Supernova’s transfer agent, prior to the extraordinary general meeting.

Our warrant holders should not submit the certificates relating to their warrants. Public shareholders who do not elect to have their public shares redeemed for the pro rata share of the trust account should not submit the certificates relating to their public shares.

Upon the Domestication, holders of Supernova units, Class A ordinary shares, Class B ordinary shares and warrants will receive shares of New Rigetti Common Stock and New Rigetti warrants, as the case may be, without needing to take any action and, accordingly, such holders should not submit any certificates relating to their units, Class A ordinary shares (unless such holder elects to redeem the public shares in accordance with the procedures set forth above), Class B ordinary shares or warrants.

Q: What should I do if I receive more than one set of voting materials?

Shareholders may receive more than one set of voting materials, including multiple copies of this proxy statement/prospectus and multiple proxy cards or voting instruction cards. For example, if you hold your shares in more than one brokerage account, you will receive a separate voting instruction card for each brokerage account in which you hold shares. If you are a holder of record and your shares are registered in more than one name, you will receive more than one proxy card. Please complete, sign, date and return each proxy card and voting instruction card that you receive in order to cast a vote with respect to all of your ordinary shares.

Q: Who will solicit and pay the cost of soliciting proxies for the extraordinary general meeting?

Supernova will pay the cost of soliciting proxies for the extraordinary general meeting. Supernova has engaged Morrow Sodali LLC to assist in the solicitation of proxies for the extraordinary general meeting. Supernova has agreed to pay Morrow Sodali LLC a fee of $37,500, plus disbursements, and will reimburse Morrow Sodali LLC for its reasonable

out-of-pocket

expenses and indemnify Morrow Sodali LLC and its affiliates against certain claims, liabilities, losses, damages and expenses. Supernova will also reimburse banks, brokers and other custodians, nominees and fiduciaries representing beneficial owners of Class A ordinary shares for their expenses in forwarding soliciting materials to beneficial owners of Class A ordinary shares and in obtaining voting instructions from those owners. Supernova’s directors and officers may also solicit proxies by telephone, by facsimile, by mail, on the Internet or in person. They will not be paid any additional amounts for soliciting proxies.

Q: Where can I find the voting results of the extraordinary general meeting?

The preliminary voting results will be announced at the extraordinary general meeting. Supernova will publish final voting results of the extraordinary general meeting in a Current Report on Form

8-K

within four business days after the extraordinary general meeting.

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Q: Who can help answer my questions?

If you have questions about the Business Combination or if you need additional copies of the proxy statement/prospectus or the enclosed proxy card you should contact:

Morrow Sodali LLC

509 Madison Avenue, New York, New York 10022

(800)

662-5200

SNII.info@investor.morrowsodali.com

You may also obtain additional information about Supernova from documents filed with the SEC by following the instructions in the section entitled

“Where You Can Find More Information; Incorporation by Reference.”

If you are a holder of public shares and you intend to seek redemption of your public shares, you will need to deliver your share certificates (if any) and other redemption forms (as applicable) (either physically or electronically) to AST, Supernova’s transfer agent, at the address below prior to the extraordinary general meeting.

Holders must complete the procedures for electing to redeem their public shares in the manner described above prior to 5:00 p.m., Eastern Time, on

(two business days before the extraordinary general meeting) in order for their shares to be redeemed.

If you have questions regarding the certification of your position or delivery of your share certificates (if any) and other redemption forms (as applicable), please contact:

American Stock Transfer & Trust Company

6201 15th Ave.

Brooklyn, New York 11219

Attention: Proxy Department

Phone: (718)

921-8200

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SUMMARY OF THE PROXY STATEMENT/PROSPECTUS

This summary highlights selected information from this proxy statement/prospectus and does not contain all of the information that is important to you. To better understand the proposals to be submitted for a vote at the extraordinary general meeting, including the Business Combination, you should read this proxy statement/prospectus, including the Annexes and other documents referred to herein, carefully and in their entirety. The Merger Agreement is the legal document that governs the Business Combination and the other transactions that will be undertaken in connection with the Business Combination. The Merger Agreement is also described in detail in this proxy statement/prospectus in the section entitled “Business Combination Proposal—The Merger Agreement.”

The Parties to the Business Combination

Supernova

Supernova is a blank check company that was incorporated on December 22, 2020 as a Cayman Islands exempted company for the purpose of effecting a merger, share exchange, asset acquisition, share purchase, reorganization or similar business combination with one or more businesses. Supernova has neither engaged in any operations nor generated any revenue to date. Based on Supernova’s business activities, it is a “shell company” as defined under the Exchange Act because it has no operations and nominal assets consisting almost entirely of cash.

On March 4, 2021, Supernova consummated an initial public offering of 34,500,000 units at an offering price of $10.00 per unit and a private placement with Sponsor of 4,450,000 private placement warrants at an offering price of $2.00 per warrant. Each unit sold in the initial public offering consists of one Class A ordinary share and

one-fourth

of one redeemable warrant.

Following the closing of Supernova’s initial public offering, an amount equal to $345,000,000 of the net proceeds from Supernova’s initial public offering and the sale of the private placement warrants was placed in the trust account. The trust account may be invested only in U.S. government treasury bills with a maturity of 185 days or less or in money market funds investing solely in United States Treasuries and meeting certain conditions under Rule

2a-7

under the Investment Company Act of 1940, as amended, which invest only in direct U.S. government obligations. As of September 30, 2021, funds in the trust account totaled $345,011,949. These funds will remain in the trust account, except for the withdrawal of interest to pay taxes, if any, until the earliest of (i) the completion of Supernova’s initial business combination, (ii) the redemption of any public shares properly tendered in connection with a shareholder vote to amend the Existing Governing Documents to modify the substance and timing of our obligation to redeem 100% of the public shares if Supernova does not complete a business combination by March 4, 2023, or (iii) the redemption of all of the public shares if Supernova is unable to complete a business combination by March 4, 2023 (unless such date is extended in accordance with the Existing Governing Documents), subject to applicable law.

Supernova’s units, public shares and public warrants are currently listed on NYSE under the symbols “SNII.U,” “SNII” and “SNII WS,” respectively.

Supernova’s principal executive office is located at 4301 50th Street NW, Suite 300 PMB 1044, Washington, D.C. 20016, and its telephone number is (202)

918-7050.

Supernova’s corporate website address is www.supernovaspac.com. Supernova’s website and the information contained on, or that can be accessed through, the website is not deemed to be incorporated by reference in, and is not considered part of, this proxy statement/prospectus.

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Rigetti

Rigetti Holdings, Inc. is a Delaware corporation incorporated on October 5, 2021. Prior to the Rigetti Holding Company Reorganization, Rigetti & Co, Inc. was a Delaware corporation incorporated on July 9, 2013, and was converted into a Delaware limited liability company on October 6, 2021 and continues as “Rigetti & Co, LLC”. Rigetti is a pioneer in full-stack quantum computing. Rigetti has operated quantum computers over the cloud since 2017 and serves global enterprise, government, and research clients through its Rigetti Quantum Cloud Services (as defined below) platform. It’s proprietary quantum-classical infrastructure provides

ultra-low

latency integration with public and private clouds for high-performance practical quantum computing. Rigetti has developed the industry’s first multi-chip quantum processor for scalable quantum computing systems. Rigetti designs and manufactures its chips

in-house

at the industry’s first dedicated and integrated quantum device manufacturing facility (“Fab-1”). Rigetti was founded in 2013 by Chad Rigetti and today employs more than 130 people, with offices in the United States, United Kingdom and Australia.

Following the Business Combination (as defined below), Rigetti will change its name to Rigetti Computing, Inc. and will be a wholly owned subsidiary of New Rigetti.

The mailing address of Rigetti’s principal office is 775 Heinz Avenue, Berkeley, CA 94710 and its telephone number is (510)

210-5550.

First Merger Sub

Supernova Merger Sub, Inc. (“First Merger Sub”) is a Delaware corporation and a wholly owned subsidiary of Supernova. First Merger Sub does not own any material assets or operate any business.

Second Merger Sub

Supernova Romeo Merger Sub, LLC (“Second Merger Sub”) is a Delaware limited liability company and a wholly owned subsidiary of Supernova. Second Merger Sub does not own any material assets or operate any business.

Proposals to be Put to the Shareholders of Supernova at the Extraordinary General Meeting

The following is a summary of the proposals to be put to the extraordinary general meeting of Supernova and certain transactions contemplated by the Merger Agreement. Each of the proposals below, except the Adjournment Proposal and the Advisory Governing Documents Proposals, is cross-conditioned on the approval of each other proposal. The Advisory Governing Documents Proposals are

non-binding

advisory proposals that are not conditions precedent to the consummation of the Business Combination and a vote against the Advisory Governing Documents Proposals will have no impact on the provisions of the new certificate of incorporation or new bylaws of New Rigetti. The Adjournment Proposal is not conditioned upon the approval of any other proposal set forth in this proxy statement/prospectus. The transactions contemplated by the Merger Agreement will be consummated only if the Condition Precedent Proposals are approved at the extraordinary general meeting.

Business Combination Proposal

As discussed in this proxy statement/prospectus, Supernova is asking its shareholders to approve by ordinary resolution the Merger Agreement, pursuant to which Supernova will become a Delaware corporation (the “Domestication”) and the parties will enter into a business combination transaction (together with the Domestication, the “Business Combination”) by which (i) First Merger Sub will merge with and into Rigetti, with Rigetti being the surviving entity in the merger (the “First Merger”), and (ii) immediately following the First Merger, Rigetti will merge with and into Second Merger Sub, with Second Merger Sub being the surviving entity in the merger (the “Second Merger” and, together with the First Merger, the “Mergers” and, together with the

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other transactions contemplated by the Merger Agreement, the “Transactions” and the closing of the Transactions, the “Closing”). In connection with the Closing, Supernova will change its name to “Rigetti Computing, Inc.”

After consideration of the factors identified and discussed in the section entitled “

Business Combination Proposal—The Supernova Board’s Reasons for the Business Combination

,” the Supernova Board concluded that the Business Combination satisfies its investment criteria, as more fully disclosed in the prospectus for Supernova’s initial public offering, including that the businesses of Rigetti had a fair market value of at least 80% of the balance of the funds in the trust account (less any deferred underwriting commissions and taxes payable on interest earned) at the time of execution of the Merger Agreement. For more information about the transactions contemplated by the Merger Agreement, see “

Business Combination Proposal

.”

Consideration to Rigetti Equityholders in the Business Combination

The value of the aggregate equity consideration to be paid to Rigetti’s equityholders is equal to the Aggregate Equity Value. At the Closing, each share of common stock and preferred stock of Rigetti that is issued and outst